Due to the decline of the ninja population, the Japanese common folk begin to consider the title “ninja” a thing to scoff at. Determined to prove the superiority of his people, he challenges warriors time and time again to prove his strength. When he hears of the opening of a portal called “Hell’s Gate”, he sets out to defeat the enemies within to prove his strength.
At the outset of The Last Blade 2, Zantetsu resides in his village, and teaches his grandson the way of the ninja in order to continue their legacy. However, he is aware that he will pass away in the near future and wishes to prove his strength once more before his eventual death. He once again travels to “Hell’s Gate” to experience a great battle.
It is heavily implied that he is Eiji Kisaragi's ancestor. He and Eiji share similar desperation moves.
Role in Super Smash Sisters
Zantetsu is an NPC ninja in Super Smash Sisters. He brings his special attacks from The Last Blade with him to battle. He can turn himself invisible making him hard to beat him in combat.