Gilgamesh

[Blue Harvest]

But, he disappears into an unknown abyss. It is analogous to a cartoon villain that falls off a cliff into the ravine.

That's not his last appearance in the game. In the battle against Necrophobia, he says his good-byes to Butz and company, then blows himself up and dies.

Ah but what if you're at a high level and defeat the boss before Gilgamesh comes along? He won't die then!