I'm starting to think that Loki represents Ragnarok itself as a concept.

Loki of course, Snake eyes(Jormungandr), and "Dogaha" laugh and a wolf pet(Fenrir). Lightning and a hammer like Thor, and it's been speculated that his Devil Fruit has fire powers like Surtur. He is the "Sun God" after all.

Loki will be extremely important in the endgame I think.