It's not a unique lore to the One Piece verse, it's the same as other regular mythical Zoan, phoenix, buddha, kirin, ookami, kitsune..
Simply Oda took inspiration from the Norse mithology, as he does with everything.
Joy Boy too was form some Javanese King, and we want to talk about Davy Jones lol? Or "Blackbeard" Teach?
Nidhogg Is a special "creature" inspired by real world lore.




