>>29541787Gen 2's Legendary Beasts died in a fire before being revived by Ho-oh, and Sinnoh myths mention Pokemon death. Gen 6 had the war AZ ended due to his Floette's death, and the Ultimate Weapon's first firing killed almost everyone. That's all I remember off the top of my head, but I know there's more.
As for an exploding Golem, I suspect "moves" used in battles aren't really lethal so much as predetermined nerf bats Pokemon hit each other with.