A battle to the death? Casshern can't kill Alucard and Alucard can kill Casshern.
@Kobra678: Dio match with Casshern didn't show any limit at all, in fact Casshern was ripped apart and got exposed by Dio
and Casshern then went on to stop Luna as if nothing happened.
Casshern has not been shown to have any limits and he was once able to survive being ripped apart.
@LHWKnight: What are you talking about? After he fought Dio, he was demolished and took a long ass time to regenerate and weren't people questioning if he even could regen? I'll see if i can find a video or the episode or something later, can't right now.
Either way, you still haven't told me anything that Casshern could do to kill Alucard.