Porky from Mother 3.
A immortal child in an old body, he accepted his evil fate.
He coughs and wheezes frequently and talks like a teen bully.
He's insane, immature, ruthless and doesn't fear death, since he's immortal.
He's a nihilist who wants to end the world by obtaining his wish from the Dark Dragon, so that everyone will be gone except him.
He pilots a spider mech whose attacks are fathomless to normal people and commands the Pigmask army and his brainwashed slave, the Masked Man.