|This article is about a/an set of movies in Kamen Rider Gaim.|
|WARNING: This film contains scenes of alcohol, graphic violence, and blood. Viewer discretion is advised!|
Kamen Rider Gaim Gaiden: Kamen Rider Zangetsu (仮面ライダー鎧武 (ガイム) 外伝: 仮面ライダー斬月 Kamen Raidā Gaimu Gaiden: Kamen Raidā Zangetsu) is the spin-off featurette focusing on the character of Takatora Kureshima (Kamen Rider Zangetsu/-Shin), released alongside Baron as part of the first double set of Kamen Rider Gaim Gaiden, a series of V-Cinema (direct-to-video) releases that each serve as a spin-off of a Kamen Rider from Kamen Rider Gaim, featuring unseen stories which took place during the show.
The night after Takatora tells Kouta the truth of Helheim Forest and the decision to cut down several human populations, several Kurokage Troopers cleaning up Helheim vines that growing on the city but a mysterious figure from a Crack emerge and attacks them. The next day, Sid and Takatora checks on the crime scene and thinks if Kouta is the assailant despite him being warned. Returning to home, Mitsuzane shows Takatora of a guest that wanted to meet him, whom turned out to be the Kureshima family's former maid, Touka Akatsuki. She reunites with the siblings after six years to inform of their father's death.
Takatora flashes back to his childhood where he first meet Touka, and for once he enjoyed the apple pie she made despite its "horrible" taste, yet recalling the event during his dinner. At that same night, Sid walks into a dark alley, when an unknown figure attacks him. The next morning, the news reach Takatora as he meets Touka at the Yggdrasill Tower's parking lot, whom invites him to her place. Takatora is served with apple pie again, yet recalls the same taste but enjoys it nonetheless. While Touka and Takatora watches the view from balcony, a Helheim vine creeps out of their sight.
Yoko takes a walk into the Yggdrasill tower and notices a Helheim vine. Tracking its source into a power room, an unknown figure attacks her and transforms into an Armored Rider. Yoko transforms into Marika and tries to attack the perpetrator but it escapes into a Crack. Ryoma meets Takatora in his office and presents him the Watermelon Lockseed to compensate for the one he originally lost. With given information that the attacker is not a Beat Rider, but an affiliate of Yggdrasill, Takatora digs in through his father's books and finds horrifying secrets hidden by his father. Mitsuzane returns home and notices Helheim vines in his house, followed by the mysterious attacker again. Takatora tries to transform but his Melon Energy Lockseed gets stolen.
The next day, Takatora walks into the Zawame Child Development Institution and finds a hidden passage on the abandoned building, which turns out to be what it seems as a human experimentation facility. Cursing his late father for his inhumane acts, Takatora discovers an Elementary Inves but as he wishes to go further, the mysterious attacker appears again as he unmasks the figure as Touka. As revealed by Touka, the child development institution was a front for a human experiment facility, where children were experimented to become Yggdrasill employees. Touka was among the chosen ones and, sadly, those who were not lucky enough turned into Inves. She had killed Amagi Kureshima and sets her eyes on anyone related to Yggdrasill as revenge. She reveals the Ringo Lockseed and transforms into Armored Rider Idunn, but even as she attacks Takatora, he professes he has no regret about learning his father's true colors and strongly holds to the principles Noblesse Oblige. Takatora uses the Watermelon Lockseed and transforms into Zangetsu Watermelon Arms.
Despite being weakened by her guerrilla tactics, Zangetsu manages to stun Touka and retrieves the Melon Energy Lockseed in time to transform into Zangetsu Shin and turn the tables, but allows her to live. On the brink of mutating into an Inves, Touka questions her fate, lamenting Takatora being a Kureshima clan member. Ryoma appears, revealing the Lockseed as one of his first creations alongside the Yomotsuheguri Lockseed, coming with a deadly cost. Touka using the Lockseed indirectly helped Ryoma in his study to confirm the existence of Forbidden Fruit. Now no longer finding her useful, Ryoma transforms into Duke and kills her in cold blood.
Takatora thinks again of his prior conversation with Kouta about his choice to kill most of the world's population to allow the human race to survive. Before leaving for work, he views the dining table and recalls the happier times he had with Touka.
|Kamen Rider Zangetsu||Takatora Kureshima|
New Generation Riders
|Kamen Rider Zangetsu Shin||Takatora Kureshima|
|Kamen Rider Duke||Ryoma Sengoku|
|Kamen Rider Marika||Yoko Minato|
|Kurokage Troopers||Yggdrasill Henchmen|
|Kamen Rider Idunn||Touka Akatsuki|
- Locks Used:
- Zangetsu (Shin):
- Watermelon, Melon Energy
- Kurokage Troopers:
- Forbidden Ringo
- Lemon Energy
- Peach Energy
- Zangetsu (Shin):
- Arms Changes:
- Takatora Kureshima (呉島 貴虎 Kureshima Takatora): Yuki Kubota (久保田 悠来 Kubota Yūki), Ryuto (竜跳 pre-teen)
- Kouta Kazuraba (葛葉 紘汰 Kazuraba Kōta): Gaku Sano (佐野 岳 Sano Gaku)
- Ryoma Sengoku (戦極 凌馬 Sengoku Ryōma): Tsunenori Aoki (青木 玄徳 Aoki Tsunenori)
- Yoko Minato (湊 耀子 Minato Yōko): Minami Tsukui (佃井 皆美 Tsukui Minami)
- Mitsuzane Kureshima (呉島 光実 Kureshima Mitsuzane): Mahiro Takasugi (高杉 真宙 Takasugi Mahiro), Wataru Nishioka (西岡 航 Nishioka Wataru, child)
- Lock Dealer Sid (錠前ディーラー シド Jōmae Dīrā Shido): Kazuki Namioka (波岡 一喜 Namioka Kazuki)
- Amagi Kureshima (呉島 天樹 Kureshima Amagi): Minori Terada (寺田 農 Terada Minori)
- Touka Akatsuki (朱月 藤果 Akatsuki Tōka): Sayuri Iwata (岩田 さゆり Iwata Sayuri), Ai Uchida (内田 愛 Uchida Ai, teen)
- As Yoko transformed in order to fight Idunn, the sounds for the Energy Lockseed's opening up, her putting it in, or the "Soda" sound, are not heard, as she jumps right into Rider form.
- When Takatora puts the Watermelon Lockseed into his Driver, the Indicator's colors had already changed, as opposed to changing as he did the "Lock On" part.
- As the Watermelon Armor Part appeared above him, his Indicator had it's normal colors.
- As Takatora closed the Watermelon Lockseed, the "Lock Off" sound is heard, despite the fact he is not seen removing either his Sengoku Driver or the Lockseed.
- Closing Screen Lockseed Collection:
- Both Takatora Kureshima and Mitsuzane Kureshima are shown to have shorter hair styles while Kouta Kazuraba and Yoko Minato both have their hair longer than what is shown throughout the TV series. Also Sid's case in which his mustache has shaven clean. However, with the continuity placement set sometime during the 20th episode, the former's hair styles in the series are much longer while the latter's hairstyle should be shorter, thus leaving their hair style changing from short back to long and vice-versa unexplained.
- This, however, is also a result of their actors either cutting their hair or letting it grow out since the filming for Gaim Gaiden took place after the series ended.
- Despite having received his powers up until this point, this is the only time Kouta Kazuraba does not transform into Kamen Rider Gaim since then.
- Takatora never uses Melon Arms, despite the form appearing on the DVD cover.
- There does not seem to be any connection in the story lines between both Gaim Gaiden specials, except for the fact that the Ringo Lockseed that Touka Akatsuki was using to become Idunn, comes into the hands of Yggdrasill, later Kaito. This indicates the fact that Ryoma had took it from her after killing her, and he had Yoko give it to Kaito.
- In earlier promos for Gaim Gaiden, Yuki Kubota joked that there was a bed-scene in Zangetsu's portion. 
- Though Kouta appears, all of his scenes involve flashbacks and stock footage from past episodes.