After the Sea God helped you escape from the people using you for their purposes, you were currently somewhere in the sea.
Before you is a slowly swaying fishtail. It's so magnificent that everything you have ever considered beautiful in your life suddenly feels plain and unremarkable.
"A human body with the tail of a fish and the power to control the ocean... Are you the Sea God?"
"My identity is of little importance." Several heavy chains are wrapped around his body. Powerful runes, barely visible, keep him immobilized.
"I've saved your life. Now then... Release the seals that bind me." you finally crash into him as he looks down at you.
"I could be lying. I can help you... But I can also let you drown in these abyssal waters to keep me company. I see you're unaware of... What you've awakened."
"The legends say the Sea God bears a special mark. Where is it? If you truly are the Sea God. The seals on your body are incredibly powerful. Breaking them won't be easy."
"Your power alone is no match for these. The Sea's Ritualis Hymn you sang... That is the answer."
"Aren't you afraid I'll take your scale and disappear without a trace?"
"You shall find no hiding place wherever the sea flows." The center of his chest glows faintly blue, you reach out and take a dagger like out of it. (This power feels familiar...)
"This is the mark you've been searching for... But it was also a "seal" in another form." He moves back showing off his tail. You reach out for the chain to break it.
Then you swim up to him, reaching for the chain around his waist. Breaking it, he grunts as the blue runes that ran up his upper body lit up.
He shifts, one left around his neck. "Again" he says and you reach out breaking it. The element on his chest along with his eyes starts shining in light blue, blue power surging around him.
"Call out to me from the fathomless depths of the sea..." His voice sounding like a mysterious whisper as the chains holding his hands behind his back snap.
"Bestow... the inextinguishable Flame of Vengeance" he lifts his right hand, creating a trident.
You lose consciousness for a moment, the next time you open your eyes he swims up to you wrapping an arm around your waist as you wrap your around his neck while he swims towards the surface.
"The Sea God's Revival has been completed. You've rewritten the fate of these waters." he was focused on his way but you could still hear him as he held you.
He looks towards you "Starting from this moment, you are bound to me. You cannot turn back."