Mutsuki Kamijo

'Mutsuki Kamijō' is the fourth and final Rider to appear in the Kamen Rider Blade'' TV series, the strongest rider in Ace Form and the third youngest Kamen Rider in the whole franchise at age 17. He is played by Takahiro Hōjō. The name "Leangle" is the derived from 'leangle" (pronounced "liangle") which is an Aboriginal club/polearm-type weapon, which is related to the Minor Arcana version of the Suit of Clubs: the Suit of Wands.

Fictional character biography
Mutsuki Kamijō (上城 睦月 Kamijō Mutsuki?) is a weak-willed 17-year-old high-school kid was chosen by the improperly sealed Category Ace of Clubs (Change Spider/Spider Undead) to use the Rider System 03 and become Kamen Rider Leangle (仮面ライダーレンゲル Kamen Raidā Rengeru?), though reluctantly at first. He gains a thirst for power as the Spider Undead takes over his mind, using him to attack the other Riders. But, later he is redeemed thanks to the sealed Tiger and Tarantula Undead giving Mutsuki the strength to force the Spider Undead out and the chance to fight on his own power, eventually allowing him to seal the Spider Undead properly and using the Rider System without any adverse effects, while psychologically properly completes him as a man capable of being a rider. Soon after, Mutsuki becomes a valuable ally to the other Kamen Riders. He is also the only Kamen Rider in the show that is based on an arachnid.

Missing Ace

After Joker/Hajime was sealed, four years have passed and Mutsuki has tried to forget about being a Kamen Rider, working to have a normal life again. This was abruptly put aside when he witnesses the Category Ace of Clubs and was compelled to transform into Kamen Rider Leangle. Together with Kenzaki, Tachibana, Kotaro, and Shiori, they figure out that Kamen Rider Glaive is really the Joker that everyone is looking for. But he still manages to take the ancient power and use it on the Riders. But thanks to Hajime's sacrifice, he, Blade, and Garren were able to defeat the Albino Joker and save the world once again. He is last seen at Amane's fourteenth birthday party.

Transformations
The Leangle system was developed through tricks and manipulation by Isaka, the Peacock Undead, who needed the sealed Spider Undead to complete it. However, as later revealed, the Undead was not sealed properly and thus manipulated his users for his own agenda. For Mutsuki to change into Leangle, he has to insert the sealed Category Ace of Clubs (Change Spider) card into his Leangle Buckle and position his buckle in front of his waist. The belt would then expand automatically around his waist. Mutsuki makes a motion with his right hand across his face and says "Henshin!" and opens a portion of his buckle. The buckle would announce "Open Up!" at this point. This would also cause a violet projection with a spider image to come out before him. Unlike Blade and Garren's method of transformation (running into their projections), Mutsuki's projection comes to him. This will complete the transformation into Leangle. The same "Open Up" system will be used for the Rider Systems of the movie-only Riders Kamen Rider Glaive, Kamen Rider Lance and Kamen Rider Larc.

Ace Form
The Ace Form is the default transformation of all Rider Systems. Rider System-03 harnesses the DNA of the Spider Undead sealed within the A: "Change Spider" Rouse Card and fuses that Mutsuki via the Leangle Buckle Rider System, transforming him into Kamen Rider Leangle. This Rider form has no distinguishing capabilities or attributes apart from any other Rider except its lancer-oriented design.