Kabamaru is a young boy raised and trained by his grandfather as a ninja. After the sudden death of his grandfather, he starts living with Mai, his grandfather’s mistress, who is a school director. He is asked to help out on struggles against other schools, as he is master of the ninja mystical arts. As time passes he will make lots of friends as well as enemies, and fall in love with Mai.

Lewd, long-haired karate kid Kotaro Shindo spends his days causing amok at the prestigious Tsurugamine Academy, until the Disciplinary Committee decides enough is enough, and puts a bounty on his luscious locks. Meanwhile other sinister forces are working in the shadows to put Kotaro to use for their own ends.

Masaru Aso was the lab assistant of geneticist Doctor Mochizuki, used as one of his experiments related the creation of the Neo Organism, enabling him to transform into a grasshopper-like being called Kamen Rider ZO. He fled into the mountainside and went into a coma before he was awakened by a telepathic call two years later with an unconscious urge to protect Hiroshi Mochizuki, the son of Doctor Mochizuki.