He is the fox with the capability to manipulate water, called Aomako(青=blue, 青魔狐=Blue Magine).
(Although lower half of his body looks like other creature's that, he is fox as well as Raiten and Hakuu...!)
His name is Harou(破浪, 破="break" or "destroy", 浪=billow).

I've thought very much about pose of his rear legs.
I wanted to draw the scene in which he is swimming vigorously.
But there was dilemma.
If I straighten his leg, although he seems to be swimming, his motion seems to be not powerful.(Harou swims in a dolphin kick.)
And even so, if I draw in his legs, although his motion seems to be powerful, he does not seems to be swimming...
After all, I decided to draw in his legs. I thought that since the background is underwater, he seems to be swimming...(笑)
(Actually, there is another Aomako. Look at background carefully...)