Shin Samurai-den Yaiba

Yaiba Kurogane grows up deep in the jungle, training with a sword beside his father and caring about little beyond finding stronger opponents. A bizarre accident carries the pair to Japan, where they end up staying with his father's old rival Raizou Mine and Raizou's daughter Sayaka after Yaiba proves himself against the strongest student at their dojo.

At school he meets Takeshi Onimaru, the first boy to defeat him cleanly and therefore the perfect rival in Yaiba's eyes. Their competition becomes something far more dangerous when Onimaru acquires a legendary blade that awakens demonic power within him. What began as a schoolboy rivalry turns into a conflict threatening everyone around them, forcing Yaiba to sharpen his sword for a reason greater than simply proving he is the strongest.