Apocalypse: Beginning Is Transformed into a Weirdo Knight

"Kamen Rider, survive in the apocalypse, kill decisively" When Mio first woke up, he was in an abandoned underground research institute, surrounded by debris. When he climbed out of the ground, what he saw was an already dilapidated doomsday. Zombies are attacking, monsters are emerging one after another, and the blue sky is shrouded in dark clouds. And he... Is no longer a human being, and has become a monster, a killing machine that can freely switch between human and monster forms. "Why is it called Mio?" "Because I am number 0." When he understands the meaning of fighting and the importance of protection, the monster's body evolves, and he... Will eventually become the final knight in the doomsday!