Mettaton is a character from the game undertale, if you don't know undertale.... Then....then just look it up..it's a game where your a character named frisk, and you fell in to a BIG place in the mountains and you want to get out so you go through a whole story and at the end you can choose is you want to stay or not.... It depends what way your going....first way is the best, it's call pasafist I don't think that's how you spell it but it's when you don't kill.....second way is genoside, it's where you kill your way to the end... That's it.