Granted, this sounds like a mashup of Capcom's Mega Man X with Konami's Castlevania, but that's not the case. Rather, Zero (aka 0) refers to the final boss of Kirby's Dream Land 3, who seems to return at the end of Kirby 64: The Crystal Shards. Despite being about as kid-friendly as a Nintendo series can be, Kirby occasionally has some pretty hardcore stuff. In this case, the form of 02 appears to be a revived 0 with a bandage and a "fallen angel" styled motif. What's more, as you battle it, the bloodshot eye at its center appears to spill blood as Kirby proceeds to damage it (hence the "Bloody Tears"). Blood in a Kirby game? Who would have ever imagined?