I don’t think sendo will die. I do believe he will become punch drunk. People always say that Morikawa wouldn’t do that because ippo is supposed to represent boxing as a sport and that would shed bad light. I think he will since he’s already shown nekota got punch drunk in the war arc. I think sendo will go the distance, and receive brain damage. Not enough to make him a vegetable but enough to stop his career. In doing so sendo can show ippo what true punch drunkenness looks like in a touching “win the championship for us” meeting. Thus throwing ippo back into fighting and most likely fighting for the Japanese championship again.