Wataru Kurenai

Wataru Kurenai (紅 渡) is Kamen Rider Kiva (仮面ライダーキバ). He is a shy young man who never lies, keeping to himself due to his hygiene obsession. Wataru works at an atelier to continue his father's legacy of violin making with a dream to create the ultimate violin, using strange methods to accomplish it. But, Wataru is destined from birth to become the current Kamen Rider Kiva as his mother is Maya of the Checkmate Four, receiving a button with a diamond encrusted crown on it from her as a baby.

He teams up with Kivat to fight the Fangire race and protect humanity from them, only because the Bloody Rose orders him to "fight". But in time, Wataru learns of his family legacy and nature as a Fangire, as well as desiring to become someone strong like his father.

Evidently, Wataru is the one who inherited the mantle of Kiva from his mother, as his full-blooded predecessor was the previous King of the Checkmate Four who attempted to destroy humanity in 1986 with Otoya taking Kivat-Bat the 2nd and using it to take him down at the cost of his life. His name translates to "crimson going over" possibly a reference to his human and Fangire bloodline. Having inherited Fangire powers from his mother, Wataru is shown able to listen the sounds of the Bloody Rose's warning notes, which activate when a Fangire is attacking nearby.

History
Left by Maya as a child to protect him from the retribution she would face, Wataru lived in the European-style manor that his father lived in. However, as the building has since said to be haunted, Wataru was referred to by his neighbors as Obaketaro (お化け太郎) for his strange appearance, later donning a mask and glasses as an adult to protect him from the "world's allergies" and using a notebook to express himself without talking. His only friend during his childhood was a boy named Taiga, who helped Wataru when he was bullied and mysteriously disappeared.

In 2008, while gathering fish bones in a third attempt to create the ultimate varnish for the ultimate violin like his father, Wataru comes across Megumi Aso, who manages to show him that his "allergies" are all in his head. He later saves her from the Horse Fangire as Kiva, countering her attempt to kill him soon after before leaving her stupefied and later saving her a second time from the Octopus Fangire.

During the events of Climax Deka, Wataru helped Ryotaro Nogami during his fight against Nega Den-O and the Nega Den-Liner.

When a female lawyer named Aya Natsukawa arrives to Wataru's home with a list of the various people that Otoya had victimized with his antics, Wataru is devastated to know a side of his father his mother never told him. After meeting Keisuke Nago and getting his advice, Wataru performs acts of moral obligation for his father's sins, until he learns that Natsukawa is the Moth Fangire and Otoya's most wounded victim. Unable to fight her, Kivat is forced to summon Garulu to supplant Wataru with his feral rage in Garulu Form so Kiva can kill the Fangire.

When Nago requests that Wataru keep an eye on Megumi in his stead, he meets a young man named Noboru, who is obsessed with Megumi himself. When Noboru reveals himself to be the Sheep Fangire, Wataru learns of Nago's hatred towards Kiva. Saddened but undaunted, Wataru manages to rescue Megumi when she is captured by the Sheep Fangire, destroying him in Basshaa Form. Since the incident, Wataru took to heart what Megumi learned from her mother: the same ideology Otoya follows: "All humans are music". Eventually, Wataru is forced to lose all of Nago's respect for him when he tries to protect the Frog Fangire, Takeo Ōmura. However, Wataru did learn from Ōmura that he needs to make a violin to call his own.

It was later that Wataru meets Kengo, whose rock and roll helps him in becoming more confident in himself. Though Wataru and Kengo have separate dreams, the two promise to help the other out so that both their dreams come true. Wataru ensures his part by protecting Kengo from the Rhinoceros Fangire, accessing Dogga Form. However, Wataru's world is turned upside again when he encounters the Lion Fangire Rook, whom he met when he was suffering amnesia. However by meeting Mami Kurasawa, a former student under his father (of which he is unaware), Wataru learns to cope with the recent Fangire events of who's evil and not by "listening to the voice in his heart."

After begrudgingly following Kengo to a fortune teller to find out who Kiva really is, Wataru loses consciousness. When he awakens, he is more confident in his abilities, but has a very sarcastic attitude. It is revealed that he is possessed, albeit unknowingly, by his father Otoya as a result of the fortune teller's ritual. While using Wataru's body, although unable to maintain possession at times, Otoya teaches Megumi how to overcome her fears of using the Ixa Knuckle and she is able to help Ixa defeat the Ladybug Fangire. When Otoya finally leaves, Wataru has no recollection on what has happened under the influence of his father's spirit.

Soon after this, at a mixer that Kengo set up, Nago has a waitress named Mio fired for accidentally spilling ice cream on his shirt. Feeling sorry for her, Wataru runs after her and finds out that they have a lot in common and they start dating with Megumi's help. However, when a berserk Grizzly Fangire tries to kill Mio, a rage awakens within Wataru that releases Tatsulot from Castle Doran who unleashes Kiva's full power, changing Kiva into his Emperor Form to mortally wound the Fangire. Before Mio took her leave, due to personal issues, Wataru promises Mio that he would get stronger for her. While the Fangire Hunters were being arrested, Wataru remembers Taiga and decides to help them out by him and Kengo joining the Fangire Hunters to battle the Crab Fangire until Nago altered history so that the Cicada Fangire's survival negated the Fangire Hunters' crisis. But in the aftermath of the fight against both Fangires, Nago learns that the button he gave to Maya ended up in Wataru's possession, explaining it to be an heirloom from his mother, setting up the events where Nago learns that Wataru is Kiva.

The fight's aftermath also caused a falling out between Wataru and Kengo when the latter's hand was injured to the point he could never play again and Wataru was trying to keep the truth from him out of not wanting him to worry. Later, Wataru is face to face with a fully grown Taiga, only to be devastated after learning that he and Mio are engaged. This stress, augmented by Kengo's return as the new Ixa user, causes the Bloody Rose to crack. Though he finishes repairing the violin, he realizes something is missing from the Bloody Rose. Then, Jiro appears to him, revealing to Wataru that his father's desires dwell within the violin. When ambushed by a Kukulkan while fighting the Horsefly Fangire, Kivat holds the monster at bay as Wataru plays the Bloody Rose, realizing his father's desires to protect all music. Infusing the violin with his own desire to find his own music, Kiva finally awakens into Flight Style to destroy the Kukulkan. However, this event causes the evoking of a weapon within Castle Doran, the Zanvat Sword of the previous King of the Checkmate Four.

Eventually, Jiro brings Wataru into Castle Doran to pull out the sword. When he discovers that he can't pull it out, he finds Mio running towards him until she is knocked out by the Rat Fangire. After destroying one, he is ambushed by two others before having to fight Kamen Rider Saga. Escaping, he finds Mio, who tells him that she loves him, not Taiga. Wataru becomes happy after this event, until he receives an invitation to Taiga and Mio's wedding. He then appears before Mio and Taiga, defending them from more Rat Fangires, while admitting his feelings to Mio. Found by Jiro, he tries to pull out the blade again, succeeding, though the Zanvat is created to limit the sword's power when it causes his Fangire blood to surface. After a brief fight with Saga, Wataru is exposed by Mio as she is revealed as the Pearlshell Fangire with Saga reverting to Taiga. Wataru runs off in confusion and hysterics before being spirited by Jiro who helps him cope with the revelations. The next day, as he and Mio discuss this, Taiga takes them to meet Maya as Wataru recognizes her. While demanding why she left him to fend for himself, Wataru learns that he is Taiga's younger half-brother.

Although confused as to why Maya never told him about any of this, Wataru slowly accepts his true identity. Wanting to share the truth, he informs Nago that he will tell everyone in the organization that he is Kiva. When Nago arranges a gathering at a restaurant, Wataru also reveals that he is half-Fangire, shocking everyone. Despite this, Shima falsely promises to help him build a world where both Fangires and humans can coexist peacefully.

Later, Wataru is approached by Taiga, who asks him to join the Fangires, and Mio, who asks him to destroy Taiga so he can be the new King. Wataru declines both of these requests, perplexed as to why both sides cannot get along. However, Taiga is persistent in getting his friend to understand his ideology that he asks the Bishop to awaken Wataru's true Fangire powers. This causes Wataru to go berserk and attack his friends, even to the extent of nearly killing Megumi. When he finally returns to normal, he becomes so traumatized from the ordeal that he completely relapses back into a recluse and completely isolates himself within his house, refusing to fight as Kiva anymore.

Though being convinced by Kengo and Nago, it took Maya's intervention to convince Wataru to fight as Kiva again, not as a human or a Fangire but as himself, so that he'll find his own music. Taiga, enraged by Wataru's decision, gives him time to reconsider. When Shima was near certain death, Taiga saved him by transplanting into him a bit of Fangire power. Wataru is appointed as Shima's bodyguard when this is revealed, as Nago was unable to bring himself to kill Shima. Shima then dies in combat with Taiga, enraging Wataru. They battle, and just as Kiva was about to finish Saga off, Mio steps in the way and takes the Emperor Moon Break as she is destroyed. However, finding her after the Bishop fatally wounds her, Wataru is left to think that he killed her and goes into despair with an equally distraught Taiga intent on killing him under the same impression.

But Jiro's interference allows Wataru to go back into 1986, meeting his father face to face just before he dons the mantle of Kiva. Though he originally came to keep his parents apart to negate his existence, Wataru learns that it would be pointless if Mio had never met him and the only way he could honor her is to live a strong life for her sake. He would ultimately play a pivotal role in the death of the original King before returning to 2008 after receiving his father's final words. With a stronger resolve, he charges into battle against the revived Fangires unleashed by the Bishop, saving Shizuka, Megumi, and Nago before confronting Taiga to settle things. In spire of interference, the fight ends with Wataru the winner though he refused to kill Taiga as he take his brother's place as the new King of the Fangires to everyone's shock. Taiga later demands Wataru to fight him again, having claimed to kill their mother to acquire the powers of Dark Kiva.

After their fight is interrupted by the Bishop and his new army of revived Fangires, the two Kivas and the Arms Monsters quickly defeat the Fangires, as the Bishop is destroyed by Nago as Rising Ixa. Wataru reveals that he had taken the mantle of the King for his brother's sake, shielding him from his enemies. By then, the revived Bat Fangire attacks the two brothers, defeating them easily. Wataru is thrown off of a cliff and encounters the spirit of his father near the discarded gauntlet of the original Ixa Prototype, telling Wataru that he lives on inside him and not to lose hope. With his father's encouraging words, both he and Taiga are able to defeat the Bat Fangire with a Snaking Death-Break and Emperor Moon Break combo. When Maya appears, Wataru is put at ease knowing that she was not really killed by Taiga as the two brothers are now on the same page and resume their fight to determine who will be the new King of the Checkmate Four.

Days later, just as he is about to play the violin at Nago and Megumi's wedding, a young man resembling Otoya bursts into the reception claiming to be Wataru's son Masao Kurenai from 22 years in the future. He warns his father of a new threat to humanity and shows him, Taiga, Nago, the Arms Monsters, and the rest of the reception a portal in the sky. Immediately in response to the situation, Wataru transforms into Kamen Rider Kiva Emperor Form. With his son as Kamen Rider New Kiva, Nago as Kamen Rider Ixa Rising Form, Taiga as Kamen Rider Dark Kiva, and the Arms Monsters at his side, Wataru confronts this new foe.

Kamen Rider Decade
Wataru's role in Kamen Rider Decade is mostly as an observer. Wataru appears before Tsukasa Kadoya as a representative of the Kamen Riders, explaining to him that something is forcibly merging the parallel worlds of the Kamen Riders and causing their destruction. The Riders give Tsukasa the task of traveling the worlds and saving them as Kamen Rider Decade, while they prevent the destruction of Natsumi Hikari's world by freezing it in time. At the end of Decade's journey, however, Wataru reappears and told Tsukasa that his true mission was to defeat the Nine Heisei Kamen Riders, not befriend them. Wataru transforms into Kiva once more in order to fight Decade and end the crisis. In Movie War 2010, following Tsukasa's destruction, Wataru explains to Natsumi and Daiki Kaito that Decade had no story of his own, instead fulfilling whatever role the Rider worlds needed him to be, and that his death has undone the destruction of the multiverse.

OOO, Den-O, All Riders: Let's Go Kamen Riders
A mishap caused by the Greeed Ankh unintentionally altered the timeline which enabled Shocker to utilize the Core Medal to create the Shocker Greeed which defeated the Double Riders and seemingly erased the legacy of the Kamen Riders from history. In 2011, after Kamen Rider New Den-O's attempt to repair the damage, he along with Kamen Rider OOO and M-Ankh awaited execution. However, it was revealed the Double Riders had their brainwashing removed by a Shocker scientist.

The Double Riders joined with New Den-O and OOO to fight Shocker's forces, but were eventually defeated. When the order was given to kill everyone, V3 suddenly appeared, asserting that there were more than four riders. V3 was soon followed by all the other revived riders that came after him, including Kiva, as even though Rider history was changed, the people's memories haven't changed.

After the riders were united, they faced off against Shocker's Great Leader. Later, when joined by a force of extra riders, Kiva and all the other riders got on their motorcycles and performed the "All Rider Break", ramming into the Rock Great Leader and defeating it once and for all.

Super Hero Taisen
Kiva, among the majority of the Kamen Riders, was caught up in the "Super Hero Taisen" incident which resulted in the Kamen Riders and Super Sentai joining forces to defeat both Dai-Shocker and Dai-Zangyack. Kiva teamed up with Tsukasa (as Decade in 1 form) and later teamed up with the Go-Ongers using the Moonbreak finisher.

Kamen Rider Wizard
"I'm going to protect these kids!"

- Kiva Kiva appears with all the Heisei Riders from Kuuga to Fourze, led by Decade, in a special two-parter after the finale, The Kamen Rider Rings and Neverending Story.

Kamen Rider Taisen
Kiva joins the Heisei Riders in their war with the Showa Riders in Zawame City. At the climax, Kiva is one of the surviving Riders in the battle between Heisei and Showa. He is defeated by Kamen Rider #1's Rider Kick, transforming him into his Lockseed. Gaim is soon left as the last Rider standing before Ambassador Darkness of the Badan Empire reveals himself to be Ryo Murasame (Kamen Rider ZX). Together, they restore the other Riders and all 30 Kamen Riders defeat the Badan Empire.

Due to the timeline alteration caused by Shocker, Kiva became one of the brainwashed Riders in that timeline, donning the name of Shocker Rider Kiva.

Following the Rider Grand Prix in which Drive emerged victorious over Rider 3, who was promptly integrated into the Great Leader of Shocker's Rider Robo form, Kiva was among the Riders who attacked Drive while being caught in the crossfire as the Rider Robo joined the fray. Ultimately, the Double Riders 1 and 2 made their appearance having survived their apparent demise from within the Rider Robo, and broke Shocker's brainwashing on the fallen Riders, enabling all Riders to unite in a final battle against Shocker.

Unfortunately, Kiva was among the Riders whose existence was erased by the Rider Robo. This fate, however, was rendered moot when the Rider Robo was finally destroyed by, restoring Kiva's place in history.

Kamen Rider Ex-Aid "Tricks": Kamen Rider Genm
Despite not appearing in the web-exclusive series, Kiva and 13 Heisei Riders were the projections of the Ganbarizing Critical Strike.

Kamen Rider Build: Be The One
Among the first 18 Heisei Riders, Kiva fought against numerous monsters in a melee briefly witnessed by Sento Kiryu before being caught in the crossfire as Kamen Rider Zi-O BuildArmor used his Vortex Time Break to wipe out his enemies.

Kamen Rider Battride War
Kamen Rider Kiva appears as a Main Rider in the video game Kamen Rider: Battride War, which unites the riders of the Heisei era from Kuuga to Wizard.

Kamen Rider Battride War II
Kamen Rider Kiva reappeared in Kamen Rider: Battride War II, summoned by Cinema along with the remaining Heisei Riders in order to create the "ultimate movie". Kiva's stage was based of from Kamen Rider Kiva: King of the Castle in the Demon World, with Kamen Rider Arc as his main enemy.

Kamen Rider: Battride War Genesis
Kamen Rider Kiva reappeared in Kamen Rider: Battride War Genesis.

Novel
In the novel reimagination of the TV series, Kiva is Wataru's Fangire form. With that, Kivat, Basshaa and Dogga do not exist in this story. Meanwhile, Jiro/Garulu, who is in turn, a Fangire Hunter. And Nago never befriends Wataru, who ends up as the final villain. He died after his Rider Kick collides with Wataru's kick.

Personality
A man who loves music greatly, Wataru Kurenai was initially a shut in whose only friends were Kivat-bat the 3rd and Shizuka. He was more shy as a child and a bit of a crybaby which led to him often being bullied by other children. Having had little interaction with others, Wataru could easily become emotional, something that Kivat-bat the 3rd constantly warned against.

Although at first glance Wataru seemed weak, he is actually quite tough in his own right, managing to live on his own as a small child without any parents to take care of him. Partly due to not having a guardian though, Wataru had a slight lack of common sense, which only worsened his unpopularity. His tendency to bring odd ingredients for violin making has been the subject of ridicule by many, with even Shizuka feeling disturbed by it.

Being a pacifist, Wataru would rather not use violence to resolve a situation, opting to instead talk things out with his foes. This gentle nature has been noted and praised by others, including Nago and Mio. However, this stance also caused Wataru to become something of a pushover, having difficulty turning down requests. Worse, it also made Wataru not have the courage to tell others what they need to hear, fearing they will become disheartened.

While initially distraught once learning of his true heritage, Wataru eventually learned to accept himself for who he truly is and realized that not all Fangires are evil. This also convinced him that humans and Fangires can co-exist, so long as they will it.

As Wataru begins to walk out of his comfort zone, he slowly but steadily becomes more confident and learns to fight for others as Kamen Rider Kiva rather than just doing so because the Bloody Rose tells him to. He also learned how to socialize more with others, being accepted by his neighbors when he faced them in a mature manner. Though he felt disheartened many times in the series, Wataru ultimately learned to believe in himself, as his father Otoya had believed in him.

By Kamen Rider Decade, Wataru has matured greatly. Remaining cool and calm throughout the series, Wataru tells Tsukasa of the grave situation and tells him to save everyone as Kamen Rider Decade. Notably though, Wataru seemed to have become quite ruthless, telling Tsukasa that he was to destroy the A.R Riders rather than befriend them. Moreover, Wataru had personally attempted to destroy Tsukasa, claiming it to be necessary for restoring the Rider words. Even after seeing Natsumi and Yusuke in distraught at losing Tsukasa, Wataru showed no sympathy towards them, something unthinkable in the original series. In Kamen Rider Wizard however, Wataru seems to have regained his kindness, showing concern towards the alternate Haruto and Koyomi.

Relationship

 * Family:
 * Otoya Kurenai: Wataru's father and a person he looked up, Wataru was told by his mother that Otoya was a great man. When Wataru learned of Otoya's troublesome actions though the Moth Fangire though, he became somewhat disillusioned and saddened at what his father had done. While saddened, Wataru still continued to love Otoya as his father. However, meeting the Frog Fangire later convinced Wataru that Otoya did have some good inside, regaining the respect he had previously lost towards him. When Wataru thought he had killed Mio, he became suicidal. Understanding that only Otoya could help him, Jiro sent Wataru into the past. Encountering Otoya, Wataru was convinced by his father that he should continue living on with his life, as that is what Mio would have wanted him to do. Witnessing Otoya sacrifice himself to stop the Bat Fangire had also left a profound effect on Wataru, giving him the strength to become a true Kamen Rider. In the final battle against the revived Bat Fangire, Otoya appeared in spirit to help Wataru, saving him from falling to his doom. Telling Wataru that he will always be there when needed, Otoya's words motivated Wataru to continue fighting and win.
 * Maya: Wataru's mother. Wataru questioned her disappearance for years because she left him when he was still a child. He did however, appear to hold no ill feelings toward Maya for leaving him. Maya dearly loved Wataru as her son, and wished they would reunite. When they had finally reunited though, there were clear tensions between mother and son. Despite this, when Wataru had lost confidence in himself due to Bishop's actions, it was Maya that healed her son's emotional pain. Appearing in his dream, Maya told Wataru that he should forgive himself for what had happened, expressing her faith in him. When Wataru met his mother after watching Otoya sacrifice himself in the past, both comforted each other over Otoya's death. Wataru told his mother that he will become a strong person like his father was, if not stronger. In response, Maya states her confidence in Wataru. By the time of the final battle, it is clear that Wataru and Maya have restored their relationship as mother and son.
 * Taiga Nobori: Wataru's half-brother. Initially regarding Wataru as his best friend, Taiga greatly cared for him, despite having a strong hatred towards humans. Wataru also cherished his friendship with Taiga, though was shocked that he was engaged with Mio. While he cared for Wataru as a friend, Taiga also somewhat looked down on him, even referring to him as a low-class human being to Mio at one point. This may have partially been from the jealousy he felt towards Wataru for being chosen by Mio as the target of her affection. Nevertheless, Taiga adamantly chose not to kill Wataru when suggested to do so by Bishop. Once both had learned of each other's identity as Kamen Rider Kiva and Saga, Taiga deduces that Wataru is his half-brother, much to his joy. Telling Wataru that he had always felt alone, Taiga tried to convince him to join the Fangire's cause to enslave humanity. Wataru's refusal to do so, as well as the rivalry they had over Mio's affections drove a wedge between the two. Things came to a head when Mio had died. Believing Wataru to have killed Mio, Taiga became bent on murdering his brother. Upon learning the truth by Bishop, Taiga made one final attempt to make Wataru his subordinate. Upon being defeated and stripped of his title as the King of Fangires, Taiga was consumed with jealousy. Challenging his brother to one final battle as Kamen Rider Dark Kiva, the two were ambushed by Bishop and his revived Fangire army. Defeating the army together, Wataru embraced Taiga and told him that he was not alone. Confused, Taiga questioned his true motive. Shima then appeared and told Taiga that Wataru was trying to protect him. The two brothers reconciling, they faced the revived Bat Fangire together. After defeating the Bat Fangire, Wataru and Taiga resumed the fight for the title as the King of Fangires, though without animosity. Later, Taiga proposed to his company of a new energy source to nourish the twelve Demon Races, showing that he has adopted Wataru's mindset about the humans. Regardless of who the victor was in the final battle, Taiga will always be there for his little brother.
 * Kivat-Bat the 3rd: Wataru's personal bodyguard and best friend, Kivat encourages Wataru to do what is right as Kamen Rider Kiva, as well as showing concern for his well-being. Wataru is very close with Kivat, often talking with him on various subjects.
 * Masao Kurenai: Wataru's son from the future, who became Kamen Rider New Kiva. Masao seems to be fond of his father, calling him "papa" and asking for his help to deal with the Neo-Fangire.
 * Castle Doran residence:
 * Jiro: Promising Otoya to help Wataru in his time of need, Jiro solemnly upholds his vow, to the point of directly assisting Wataru when necessary. When Wataru tried to deny the fact that he learned Mio and Taiga's identity as the Pearlshell Fangire and Kamen Rider Saga, Jiro slapped him out of his dilemma and sternly told him to not avert his eyes from reality. Immediately afterwards, Jiro states that both he and Otoya's soul are watching Wataru, and tells him not to be a disappointment. When Wataru became suicidal from Mio's death, Jiro was the one who saved him from Taiga's wrath, as well as being the one that sent him into the past to meet his father. This proved vital for Wataru to regain his will to live. Much later, when Wataru proclaimed that he would become the new King of Fangires, Jiro was shocked and initially tried to dissuade him from doing so. When Wataru fiercely showed his determination though, Jiro complied, bowing down towards him as a servant.
 * Ramon: Before meeting Wataru personally, Ramon seemed to be rather aloof towards Otoya's son. At one point, he had even suggested to the other Arm Monsters that they eat Wataru to be released from service. When the two had met each other however, Ramon began affectionately referring to Wataru as "Onii-chan" and decided to help him. Alongside Jiro and Riki, Ramon became Wataru's servant when he proclaimed himself as the new King of Fangires, showing that he genuinely respects Wataru's power.
 * Riki: Unlike Jiro, Riki does not seem to be particularly concerned with Wataru in general, even agreeing with Ramon's proposal to eat him. Since Jiro will not allow such an act though, Riki continues to assist him. Notably though, when Wataru proclaimed himself the new King of Fangires, Riki became an obedient servant, showing that he has come to respect Otoya's son.
 * Tatsulot: Wataru's second personal bodyguard, Tatsulot acts as his supporter in a manner similar to Kivat-Bat the 3rd,
 * Allies:
 * Shizuka Nomura: Wataru's good friend, Shizuka is revealed to be slightly attracted towards him. Despite Wataru being percieved as odd by others, Shizuka knows the good he has inside and will support him in his time of need.
 * Keisuke Nago: When they first met, Wataru thought of Nago as a sort of mentor, while Nago saw Wataru as somewhat weak and indecisive, but ultimately a kindhearted figure. Since he did not know of Wataru's identity as Kamen Rider Kiva, Nago would constantly attack him as Kamen Rider Ixa, to Wataru's chagrin. Upon going to the past and meeting with Otoya though, Nago had become kinder and showed more respect towards Wataru. Once he learned of Wataru's alter-ego, Nago accepted him as a fellow warrior and encouraged him to fight alongside the Wonderful Blue Sky Organization. Even when learning of Wataru's half Fangire nature, Nago continued to trust him and acted as a friend.
 * Megumi Aso: Wataru's ally. Megumi saw him as a strange and meek boy who needed to become more socially adept. While generally nice to him, Megumi could be somewhat condescending towards Wataru, mistakenly thinking of him as weak. Initially seeing Kamen Rider Kiva as an enemy, Megumi attacked him on a number of occasions. After being saved by Wataru as Kiva though, Megumi decided that he is an ally. When Wataru revealed his identity as Kamen Rider Kiva, Megumi initially did not take it seriously, before Nago confirmed it himself. This caused Megumi to see Wataru in a different light, though still caring for him as her friend. Even when Shima ordered for Wataru's termination, Megumi knew she could not do such a thing. Much like Nago and later Kengo, Megumi believes in Wataru regardless of his heritage and knows he will do what is right.
 * Kengo Eritate: Kengo admires Wataru's musical skills and acknowledges him as the kindest person he knows. When Wataru was being harassed by a trio of bulies, Kengo fought them to help his friend. When Kengo lost his ability to play the guitar though, Wataru could not bring himself to tell Kengo the bad news. Instead he encouraged Kengo that his hand wil heal completely. This however, caused Kengo to feel anger at Wataru upon learning the truth. Losing the respect he had for Wataru, Kengo broke off their friendship and acted in a violently rude manner towards him. Even when learning of Wataru's identity as Kamen Rider Kiva, Kengo continued to feel hatred towards him and tried to kill him with the Ixa system. When Wataru saved him from Bishop though, Kengo felt immense regret at what he had done. Wholeheartedly apologizing to Wataru for his previous actions, Kengo admitted that he had only used Wataru as a scapegoat to not face his own weakness as a person. Though Wataru felt hesitant at becoming friends again with Kengo due to being plagued with self-doubt, they eventually mended their friendship.
 * Mio Suzuki: Wataru was attracted with Mio and wanted to have an intimate relationship with her. The feeling was mutual, with Mio hoping that she and Wataru could get together as a couple. Due to her status as the Queen of Fangire though, the two could not form such a relationship. Worse, their relationship had soured Wataru's relationship with Taiga, further complicating things. When Mio had seemingly died from being struck by Wataru's Rider Kick, Wataru went to the past to make it so that he was never born. Yuri and Otoya convinced him though, that Mio would have wanted Wataru to live his life, with Mio appearing in spirit to confirm this before dissipating. This allowed Wataru to regain his will to live, as he now knows that that the time he spent with Mio would continue to remain in his heart. It is unknown if Wataru ever learned the truth about Mio's death, though it is likely that Taiga told him later on.
 * Mamoru Shima: While Shima initially did not see anything noteworthy of Wataru, aside from being Otoya's son, things changed when Wataru revealed his identity as Kamen Rider Kiva. Shima then saw Wataru as an enemy while rejecting his dreams of humans and Fangires co-existing. Seeing him as an even greater threat than the entire Fangire race, Shima would attempted to form a temporary alliance with Taiga to destroy Kamen Rider Kiva. The love that Nago, Megumi, and Kengo had for Wataru as their dear friend changed Shima's mind though. Shima eventually decided that Wataru could help the Wonderful Blue Sky Organization protect humanity from the Fangire race. When Taiga made it so that Shima would become a Fangire, the latter came to recognize how poorly he treated Wataru and apologized. When it looked as though Taiga had murdered Shima, Wataru was overcome with anger. This was to the extent where he nearly killed Taiga, were it not for Mio's intervention. When Shima later reappeared alive and well, he told Wataru what had really happened and asked that he protect Taiga. Wataru complied and did what he thought as necessary. When Taiga questioned Wataru's motives, Shima explained Wataru's intention, helping the two brothers reconcile.

Fighting skills
Even though he is the son of Otoya and Maya, Wataru was initially not very good at fighting. While he actually has immense strength, Wataru's lack of confidence prevented him from fighting to his fullest or even doing more than six push ups. This is hinted when Otoya's spirit possesses Wataru's body at one point, easily defeating three thugs with no trouble.

After defeating the Bat Fangire with his father, Wataru became more confident in himself, thus learning to to better utilize his powers. Even in human form, he swiftly overpowered the revived Warthog Fangire, one of the most physically powerful Fangire introduced in the series.

It is hinted in Kamen Rider Decade that Wataru is still continuing to grow in power, seemingly managing to defeat the combined forces of Shocker combatmen, Orphonochs, Fangires and the revived Bat Fangire with help from Takumi Inui/Kamen Rider Faiz. This is noteworthy as he was originally unable to defeat the Bat Fangire alone, even with or without help from Otoya or Taiga as Kamen Rider Dark Kiva until being greatly motivated.

Forms
Kiva has multiple forms that provide him with different weapons and abilities, mostly all invoked by inserting Fuestles into Kivat's mouth. Kiva's motif is that of a vampire, with his final attacks inherited from Maya. However, unlike the Fangire King, Wataru's nature as a human-fangire hybrid initially left him unable to fully utilize Kiva's full power with the Catena (カテナ) Chains serving as restraints. His fighting power may also slightly depend on Kivat-bat the 3rd's condition as shown when Kivat caught a cold. Additionally, Zanbat serves as a restraint to keep the power of the Zanvat Sword from taking complete control of Wataru.

As the series progresses, Wataru learns to better control his Fangire powers, with Taiga hinting near the end that that he can now even turn into Kamen Rider Dark Kiva if given the opportunity.

Bloody Rose


A unique violin, the Bloody Rose (ブラッディ・ローズ) was created by Otoya and Maya as the "ultimate violin", later rumored to be a product of Otoya selling his soul to the devil himself, which is not entirely false, in a sense. The Bloody Rose only sounds whenever a violent Fangire is detected in the area, its music only heard by Kivat and Wataru, who hears it as a voice commanding him to "Fight", as it pinpoints the exact location the Fangire could be found. When played, the Bloody Rose can also disrupt a Fangire's activity. However, the Bloody Rose is sympathetic to Wataru's mentality as it cracked when he fell into a deep depression. However, after repairing it, Wataru learns the Bloody Rose holds the desires of his father, placing in it his own desire which allowed him to assume Flight Style.

Devices

 * Kivat-bat the 3rd - Wataru's Kivat partner.
 * Demon Imperial Dragon Tatsulot - Wataru's second partner and the catalyst of allowing Kiva to assume Emperor Form.
 * Kivat Belt - Transformation device that forms when Kivat bites Wataru.
 * Fuestles - Whistle-like devices that activate a function, depending on the Fuestle.

Weapons

 * Demon-Beast Sword Garulu Saber - Kiva's form-changing weapon that turns him into Garulu Form.
 * Demon Sea Gun Bashaa Magnum - Kiva's form-changing weapon that turns him into Bassha Form.
 * Demon Iron Hammer Dogga Hammer - Kiva's form-changing weapon that turns him into Dogga Form.
 * Demon Imperial Sword Zanvat Sword - Kiva's personal weapon whose finisher is locked to Emperor Form.

Vehicles

 * Machine Kivaa - Kiva's Rider Machine.
 * Buroon Booster - The combination between Machine Kivaa and the artificial Demon Statue Buroon.
 * Castle Doran - Kiva's Doran partner that is also a base.
 * Shoodoran - Castle Doran's drake, which is summoned by Doran's roar in times of trouble due to being too young to be bound to a Fuestle.

Portrayal
Wataru Kurenai is portayed by Koji Seto (瀬戸 康史), who reprised his role in Kamen Rider Decade for the first and last episodes as well as in Kamen Rider × Kamen Rider W & Decade: Movie War 2010. As a child, he was portrayed by Yohei Itagaki (板垣 陽平).

As Kamen Rider Kiva, his suit actor was Seiji Takaiwa (高岩 成二).

Rider No.
As the leading Rider protagonist of Kamen Rider Kiva, Wataru Kurenai (Kamen Rider Kiva) is labeled Kamen Rider #24 (仮面ライダー24号) and Heisei Rider #9 (平成ライダー9号).