Kevin has aquatic powers, letting him survive indefinitely underwater. His vision is adapted to the higher end of the light spectrum, letting him see in the ocean depth. He has strength and invulnerability to deal with the water pressure, letting him withstand small-caliber rounds. Kevin is amphibious and can survive in both an oxygen and a water atmosphere, and can telepathically communicate with fish. He dives really well.
Personality-wise, Kevin is a jerk who forces women to give him sexual favors whenever he can get. He considers himself one of the most powerful members of the Seven, although the others think him a joke. His strength and invulnerability are nowhere on the scale of Homelander or Queen Maeve, he's not as indestructible as Translucent, lacks the sheer power and speed of A-Train, and has none of the skill and expertise of Black Noir. The Deep is leery of using his supposed influence on anyone who he believes can defeat him.
