The Great Other isn't a Westerosi concept in the first place. It's the foil to R'hllor, and yeah, Melisandre seems to associate Bloodraven with it in her visions. But visions are misleading by nature. The Drowned God's enemy is the Storm God, who is said to "live in a cloudy hall and ravens are his creatures." It could be that through the power of the Last Greenseer, Bloodraven was able to insert himself into different times and places, his presence being a part of myths and legends. It's just speculation, since stuff like that creates those pesky time paradoxes. Or it could just be a coincidence, as Ravens typically represent stuff like death, wisdom, thought, memory, etc.Whats the deal with Bloodraven and the Great Other....
Did he used to be it?
Night king has that raven sigil....is there some relevance between the two?
If so...idk why night king was trying to kill him so bad.
Raven sigil? The thing around his neck? Idk if that's plainly a raven. Not sure I'd put much meaning into the Night King's design either, as he only exists in stories in the books. But the story states that he was a former Lord Commander of the Night's Watch, just like Bloodraven, and they're obviously associated with ravens.