Thats why I have one dope idea for an RPG, OP
You start the game playing as the "warriors of light" reaching the end boss. You try to defeat him, but you can't. He defeats you, everyone gets killed, world ends.
Then the end boss enjoy his world domination for some centuries, but eventually gets bored. No one to challenge him.
So he disguises himself as a human and go find the reincarnations of all the "warriors of light" to prep them to take down the end boss (himself)
Monsters would recognize you during battle and would be afraid to hit you, only hurting your party. You are immortal, so you "die" when all your team mates fall in battle, but you take no hits.
Gimme money to make a pixel RPG like this, Square