taking an angsty route here,,, how about siren mg being an outcast in his pod cause he's born with a defect (his voice has a lower register than the rest and thus cannot attract prey the way the rest can) and so he leaves and spends the rest of his life alone..

hungry and unmated, he wanders the sea... only for him to stumble upon a cruise ship one night with a live band performing. he hears dk singing and is immediately struck with how beautiful his voice is, and in his fascination he completely misses the tall tale signs of a strom..

the storm strikes the ship and tips it over, and he watches as dk falls in the water in horror.

without thinking, mg immediately swims after him, desperate to save the one human who's voice has managed to move him in ways he has never felt before.

i can't imagine their story to end happily... but i'd like to think that their love was real..