Aquaman. CLASS 2-3 (or 60, by some sources), people! On ground! Telepathy! Can give mindblasts!
Arthur's body is naturally conditioned survive in all regions of his kingdom, and this means being able to move freely in the shallow waters of any coastline, to being able to walk on the floor of the deepest trenches in the seabed. To allow for this, Arthur's body has to be incredibly dense, and thus he weighs (out of the water) about three hundred and fifty pounds, making him one heck of a catch were he to be reeled in. But this increased density is what allows Arthur to move underwater as though he were someone on land, so while a human is slower due to a sufficient amount of 'drag' in water, Arthur is unaffected by this. He can run on the ocean's floor as though he were a sprinter on land, as well as to not be crushed when descending to great depths. This is also what allows him to reach speeds just in excess of a hundred miles per hour when swimming, despite his weight.
When out of water, Arthur maintains this density and his natural strength to wield it when on land, and thus he appears to have superhuman strength, speed and durability when exposed to the air. This is only a result of his being at a weaker pressure than he is accustomed to. On land, Arthur's reflexes are about five times faster than that of an average man's, which may only be enough to dodge a blow here or there, but not do things like snag projectiles out of the air (as that is more training than natural ability anyway). He can sprint up to speeds just greater than any Olympic athlete. Also on land, he can leap distances of one hundred feet and up to heights of twenty feet in a single bound (though underwater, it is 'normal', like what it would be for a normal person on land). His skin is dense enough to have a consistency like Kevlar, and thus bulletproof, and especially resilient to blunt attacks such as bludgeoning blows from bars, bats or punches, but can still easily be sliced or pierced (same levels apply for underwater). His density also allows him to lift weights up to that of about two to three tons, meaning he can bend metal bars, push free a beached whale (normally with help), hold up a collapsing wall, toss a car a city block, or even capsize a small fishing trolley.