Easy to figure: he is an aqua demon. Unlike Raystorm he is quite fast on normal terrain. His body shows a lot of muscles and gristle like an amphibian (but he won't croak ;P ).

With his skin he can survive as long as he wants under water. The skin lets him "eat" microorganisms and if there are none in the water or it is polluted, he can survive with his life force for a while.

His yellow-green eyes let him see in the dark. The catalyst vessels (red stripes) let him swip at high speed through water without moving arms nor legs.