This is the one that turns a high school turf war into a blood feud with swords, and it never once blinks at how ridiculous that is. Kurumada's DNA is all over it: martial arts academies as battlegrounds, a rival school poaching talent like it's a crime syndicate, and a ninja clan summoned in like artillery because Himeko Hojo refuses to let Hakuo Gakuin die quietly. Kojirou shows up grinning while everyone else is panicking, and the Yasha clan hits back with the kind of named-attack theatrics that only work if the animators fully commit. This is 1990 OVA budget doing what TV never could, hand-drawn impact frames, held reaction shots, blood that actually lands on the frame. If you grew up on Saint Seiya and wanted it with katanas and a school uniform, here you go.

Hakuo Gakuin, once a prestigious high school known for martial arts, is sliding into decline as its rival Seishikan underhandedly lures away its best students. To turn things around, acting principal Hojo Himeko sends Yagyu Ranko to Fuma Village to seek help from the famous Fuma ninja clan. The Fuma leader dispatches Kojiro to Hakuo, where he comes up against the notorious Yasha clan, who fight on Seishikan's behalf under Asuka Musashi. Once Kojiro's comrades arrive, a ninja war between the two clans, held off for 500 years, erupts in full. Expect a six-episode action OVA built around clashing ninja clans.