Two things:
1) It's basically confirmed by Kaido/BM, that it's really Oden's haki inside Enma. I don't like that writing decision at all, really feels like Zoro was just granted a magical sword. It feels like a really cheap powerup. Before some Zoro stans come at me again: I said the exact same thing about Sanji's raid suit.
2) Orochi is also basically confirmed to be alive. Yes, you read it right. Oda would never show the decapitated head of a person, who actually died due to that decapitation. Just look at Doflamingo's "decapitation" back in Dressrosa - Oda only showed the "decapitation", because Doflamingo was actually alive and well.
This one Orochi panel alone is 99.999% confirmation, that Orochi is indeed alive and Kaido's attack didn't kill him (probably due to the Yamato No Mi DF).