merman
mûr′măn″, -mən
noun
A legendary sea creature having the head and upper body of a man and the tail of a fish.A fabulous man of the sea, with the lower part of the body that of a fish.In heraldry, same as triton.
Interesting about the submissive necklace, anon, like a dog collar.
The shape of her face reminds me of this one here.