You know what a weird final boss is? Zero Two from Kirby 64: The Crystal Shards. Basically, it's some kind of evil demonic eyeball monster that is supposed to be a fallen angel. If you look closely you can see its halo. Final video game bosses can be pretty darn weird...
A final boss can either tie together a story or ruin it. Persona 5 stuck to tradition and had a phenomenal final boss that really put a bow on the story.
