Well I like sharp, pointy, destructive things, so Bakusaiga it is!
Bakusaiga can decompose any living thing that's cut with it's blade. The body begins to deteriorate, regardless of regenerative abilities. Anything that comes into contact with the perishing body will start to rot as well. Bakusaiga can also fire blasts of yoki that are capable of destroying thousands at once.
So basically, I could kill anyone with a single cut or less. I could even kill Wolverine if so inclined haha But Wolverine's my favorite so I wouldn't do that.
And if anyone wants to throw in Juuzo's scythe for me, I'll be your best friend foreva!