[Coldsaturn]

Yeah in ToR it looks like he was "awake" while chained for thousands of years, whereas he only mentions talking to MC when she's trapped in the tower in Romirro after the coup. It might be that he truly slumbers when she's not alive, or maybe the "awakening" (he also says it as a kid when they meet for the first time in present time "You awakened me") refers to the power of the Sea God, which he can only take when she's with him. Or his memories, which are partly unlocked when their bond activates again.

I think it's pretty much confirmed that her reincarnations are not sequential, and are also fragmented in different timelines. And speaking of "fragmented rebirth", that's something Raf will mention in his card "Blossoms". I'll be curious to know your thoughts on it when you'll happen to watch it.