Mermen (Prime Zone Post GW Timeline)

Mermen are magical sea creatures who are the male counterparts of mermaids with the upper half of a human and the lower part of a fish, and live underwater. However unlike mermaids who possess fairy-like wings, they appear to have a single fin found over the backbone. Unlike some fish that live in specific climates, Tritons and Mermaids have a natural ability to fit back on any temperature in water.

History on Mobius
Little is known of the Mermens history on this world and it is rumored that after the Great war that they just desapired