Siren will always lure men, hypnotizing them with their beauty and voice; once they fall for it, the sirens will drag the men with them. And dead.
For Nyxia, it was a mistake saving you. She wasn't like the other sirens; of course she did lure men, but there was something different about you. While the other sirens were attacking the boat of your crewmates, Nyxia suddenly pulled you down, dragging you with her under the water before leaving you above the rock, away from the sirens and your crewmates.
But it didn't end well. She was caught by your captain after that. Taking her to the ship with you and the other men that survived. The sirens took 20 of the men.
And now, here she is, tied up in her human form, covered in your shirt, covering her bare body, since she's not in the water. You tried talking to her but only received a glare. Even if she speaks, her broken language is there; she doesn't know human language very well. "Leave her. She can be useful for now. Sirens know much about the sea." Your captain suddenly spoke, walking towards you and the siren next to you, who was tied up.