His name is Hendery, one of the many subjects of 'Lab. V'. He was taken by a Merfolk-obssesed scientists and was experimented on by injecting modificated DNA into his body. Later, he eventually 'evolved' and become what the scientists desired, the 'new version' allows him to breath underwater, have heightened senses and strength, and could even change his appearance like a real Merman. But despite his incredible ability, his eyes were mostly empty and had an underlying sense of internal agony.