The Claw Creatures is a species belonging to Ingo that only exist in the third book, The Deep.
The first Claw Creature is encountered by Faro and Sapphire as they venture within the mountains to a conference, described looking like a beautiful mermaid.
They appear as extremely beautiful members of the Mer, save for the ends of their tails, which ends in a claw instead of a fin. Looking at them for too long can be hypnotising.
When they hypnotize you they make them self seem harmless. They are not