Thread:Bobjosh175/@comment-24448826-20180407064802/@comment-27075564-20180411214514

Sirens don't transform (they're always a human/fish with wings hybrid). If you're thinking of Sh'eenaz, it's explained in the story she found someone who could transform her to human but it's permanent, she can't switch back freely to mermaid.

The Crones, yes.