If you had to save the world...

[LandoCristo]

Gordon Freeman
Han Solo
Superman, just because he's incredibly OP against everything except kryptonite, which is an incredibly rare element, except not really, because Lex Luthor manages to build entire freaking Doom-fortresses out of the damn stuff, so it basically becomes some evil Deus Ex Machina against Superman, which really sucks for him.

 

[Harbinger_]

Kefka from Final Fantasy VI (Post WoB)
The Lone Wanderer from Fallout 3
Garrosh Hellscream from WoW

Don't know about Kefka. He seems like the sort who would just let the apocalypse happen while laughing maniacly and screaming "Diediediediediediedie!"

Oh no, you see Kefka would have to say the world because he can't let anyone else destroy it if that person/thing/event isn't him.