Feedback requested can someone help me?

[Coca-Cola]

So I made a DND OC, and I might need some help.
On a nondiscript boat, a human pirate named Dave sailed across the sea, stealing, killing, and plundering. one day while sailing he saw something in the water it was damn near the most beautiful woman he ever saw in his life and she seemed to be half way under the water. He helped her up and saw she was a siren. he quickly killed her even though he felt regret when he found out his crew was starving, he found the dead siren, cooked her and with a heavy heart served her to his crew they ate well that night and they all went to sleep that night full. But the pirate woke up at 3:00 in the morning and felt sharp pain in his legs he looked down and saw that they were green and were scaliy he ran and got out of his room as his feet fused together he knew that he was in danger. He jumped into the water and that is where his transformastion was compliet
I need help with some of the curse any help welcome

 

[Idea]

To be clear is this for actual DnD (as in, with mechanics) or is it for a DnD-inspired setting but not mechanics.

 

[Coca-Cola]

To be clear is this for actual DnD (as in, with mechanics) or is it for a DnD-inspired setting but not mechanics.

It's for ACTUAL DnD (My friends are helping me get sarted

 

[Idea]

It's for ACTUAL DnD (My friends are helping me get sarted

Noted. I don't think there is a mechanically feasible way to be a permanently water-locked character. How does your character's curse work? Or do you also want help figuring that part out?

 

[Steve Jobs]

Depending on what the campaign entails, it would be fairly impractical to have a character that can't walk on solid ground. I would heavily consider changing it to the classic "if his legs get wet, he'll change back" thing and perhaps, a water dependence (similar to the Grung).

If I were you, I would base everything off of the Siren monster in DnD (there's one in the Tomb of Horrors module), Planeshift Ixalan (they have Siren and Merfolk), or look for a homebrew race that isn't over powered. It is important to note however, that the D&D version of a Siren is closer to that of the Odyssey (i.e. harpies) than the Classical era mermaid. This one seems to fit what you're looking for, though the Level 5 perk could be changed out to something more fitting.