I think I'd give it to Sephiroth.
When he's in your party, it's not just a little slice of the game to show off how cool or powerful the antagonist is, it's a huge plot point that sets off the entire story. The characters that were involved in it spend most of the game dealing with the impact of it and coming to terms with what actually transpired.
And that blood is so real, because I just can't fake it.
My bass guitar sound- https://vocaroo.com/17qBOSAFwIfM