Laughing Banana
Weeping Pickle
He says as much. He admits his strategy is to hold out until his opponents get tired in every battle because he won't die from small attacks.
Well, he is good but the mangaka seems so fond on throwing enemies upon enemies to him that are way beyond his capacity to deal in normal circumstances. He is like Sanosuke from Rurouni Kenshin--capable, but the rest of characters in the manga is like Shishio or Kenshin's level.
Well I guess it's purposefully set up as such so the manga can play with his immortality aspect as much as possible. Its unique though, I give it that.
I also really like the relationship he has with Rin. The romance between those two is so... well, it's weird to use this word for a manga where people gets decapitated daily but... adorable.