Mermaidyn

Mermaidyn appeared in 2014 video game called Yo-Kai Watch 2. Mermaidyn (Japanese: にんぎょ Ningyo) is a Rank D, Water-attribute Classic Yo-kai of the Slippery tribe.

Mermaidyn evolves into Mermadonna when fused with a Mermaid's Jewel.

Mermaidyn can also evolve into Scaremaiden when fused with an Essence of Evil.

Mermaidyn are fair-skinned mermaids with sapphire eyes and black hair tied into a chigo mage (Japanese ringed hairstyle). Side locks hang past her pointy ears and she has dot eyebrows. She wears seashells to cover her chest and a pale blue hagoromo. The fish tail is red with a white fin fading to pink, with a matching one on top of her head.

Mermaidyn are elusive but generally patient creatures who might sometimes be fished up by accident. The Mermaidyn that appears in the anime, however, seems fated to be the only thing Nate can ever fish up no matter what, and as a result is far more foul-tempered around him. She also refuses to go along with the mischief the other Classic Yo-kai get up to on Halloween, but winds up dragged along, proclaiming it as a bad idea, being proven right as the Yo-kai are baited into revealing their monstrous true natures by hecklers.

Mermaidyn likes to spend a lot of time improving her appearance, such as with Yoga, facial treatments, and even bedazzling her tail.

For some odd reason, Nate is only ever able to fish up one particular Mermaidyn, rather than normal fish, no matter where he goes fishing. Lakes, streams, bathtubs, buckets, even puddles in the road all turn up Mermaidyn. Mermaidyn was patient with Nate at first, but became irritated the more Nate unintentionally fished her up, finally giving Nate her medal on the agreement that he never fish ever again. Nate is about as thrilled with their fated arrangement as Mermaidyn is, though he has invoked their relationship once during Halloween, where she exclaims that Nate should simply have used his medal.