Len

Len is a mysterious figure who is fighting Xaviax's monsters who has the ability to transform into Kamen Rider Wing Knight armed with a bat Advent Deck. He is aloof in personality and tries to keep the Riders' existence a mystery from the public. His Advent Beast is Black Wing, a bat. He is one of the original Kamen Riders from Ventara prior to their betrayal by his best friend Adam, the original Dragon Knight. At first, Len did not want Kit to get involved with his problems or become Dragon Knight. But once Kit used the Advent Deck, they agreed to defeat Xaviax and save Kit's world.

History
While he vented Incisor without hesitation, he begins to start hesitating when he was confronted by Thrust and Sting hoping to save them and have them fight against Xaviax. Doubting himself, Len reflects and reminds himself that he is fighting in a war against Xaviax in which sacrifices must be made and that he cannot save everyone. He reflects on this again when Chris is vented, saying he should not have been involved. He also feels pressure from being forced into a leadership role that he never intended to take, but resolves to carry out his mission regardless. Len and Kit are slowly developing a close friendship, possibly due in part to Kit being the Earth counterpart of Adam.

He was chosen to be a Kamen Rider at a young age due to his excellent physical condition, and considered it an honor to fight for Ventara. Recently, Len was reunited with Kase, Kamen Rider Siren and Len's girlfriend, who survived Ventara's destruction. He starts to notice that Kit is not being himself since Kase came back and thinking he needs some time, decides that when Kit is ready to become a real Kamen Rider, he can fight with them once more. After listening to Kit talk about his conversation with Xaviax as well as his resolve to fight against him, he welcomes back Kit as he accepts his offer to become a real Kamen Rider.

When Kit goes to talk to his father, Len and Kase sense Strike and Wrath. He finds that Xaviax has hijacked Wrath's body to directly fight him, something which insults Len since the original Wrath was his mentor. They are overpowered by their combined force but escape before they receive any more injuries. During their next encounter, he was able to turn the fight on Wrath, but let him go to find Kase and Kit. When Trent gives him the location of the No-Men, Len and Kase break into the building to rescue Kit. They find Kit being attacked by Strike and Wrath and successfully retreat with Kit. Kase shows Len his Survive card and soon they go off to fight Wrath and Strike. However, JTC manages to steal the Thrust and Sting decks from him only to use those two decks against them.

After a long battle, with the group severely weakened, Strike manages to vent Kase. Losing his girlfriend twice to the war, Len chooses to go after Strike with nothing but revenge on his mind. He immediately triggers Survive Mode, and after a short battle with JTC their Final Vents collide, taking Len out of Survive Mode but venting Strike in the process. Wrath shows up and and takes on both Len and Kit in their Survive Modes. Wrath proves to be too strong as he overpowers both of them and in the process vents Kit and Vic, but the body of Xaviax is unaffected. History repeats itself as Len once again becomes the only Rider remaining in the war against Xaviax. When all hope is lost, Len acquires a letter from Michele Walsh and says that they can still win the war.

Walsh' secret weapon proved to be a stasis-bound Eubulon, the man who gave the Kamen Riders their Advent Decks. Len was able to revive him, and Eubulon then reassigned the Siren Deck to Maya Young so that she could fight alongside Len while he attempted to rescue the other Kamen Riders from the Advent Void. They would soon be forced to deal with the return of Adam, who had been given his Advent Deck again by Xaviax, claiming that Xaviax had deceived him. Several of the other Ventaran Riders were soon rescued and joined them, and they set out to sabotage Xaviax's transport machines and thus prevent him from abducting Earth's population. They were then unexpectedly joined by Kit, who had returned and taken up the new mantle of Kamen Rider Onyx. Kase was returned as well, though badly weakened, and Adam was then welcomed back into the group by Eubulon despite Len's misgivings.

Len's fears would prove truth, as Adam deceived the Riders again before outright betraying them, culminating in a showdown between the two old friends that ended with Len taking Adam's Advent Deck. However, Adam eventually proved to be truly repentant, and joined Len, Kit, and Kase in battling Xaviax. They were eventually joined by Eubulon and the other Ventaran Riders, and destroyed their foe once and for all using their Link Vent. With their mission accomplished, the Kamen Riders set out to restore Ventara, with Adam stepping down and passing the mantle of Dragon Knight permanently to Kit.