Philip Chang sent his son into hiding while he was still an infant. Born in Hong Kong but raised in Seattle, Percival Edmund soon became known as "Grunge", an all-American slacker who knew little about his brave father. He was eventually invited to take part in I.O.'s Project Genesis, where Grunge soon found out he was in a prison-like breeding ground for Gen-Actives. Manifesting his powers, he escaped with his new teammates, a group soon to be called Gen¹³. Grunge is a skater/surfer and enjoys spending his afternoons sleeping in. Although he lives in a beach house with three beautiful superwomen, only Freefall appreciates him for who he really is. However this never stops Grunge from trying to hit on the others constantly.
While on the surface seeming to be nothing more that a typical frat boy type, there is more to Grunge than he lets on. He also has a photographic memory but tends to keep this fact to himself for fear of being thought a nerd. Grunge is also an avid fan of comic books and Hong Kong Kung Fu movies and action films. He especially likes the films of Bruce Lee, Jackie Chan, and John Woo.
Molecular Reconstruction: Grunge has the ability to molecularly bond with anything he comes in contact with. Once he bonds with an object he takes on its physical characteristics. For example, if he bonds with steel he gains increased strength and durability. The limits of his absorption ability were never revealed. The full extent of his powers was never fully addressed, with certain abilities seeming to appear out of nowhere and cease to be used soon after. It is revealed that he can actually assume the shape of objects he absorbs.
Phasing: He at times was able to meld with the ground beneath him sinking his hands at one place and having them come up at another place. He has also absorbed the properties of sand, from sand in his boot. Instead of gaining the properties of a rock, as sand is just small stones, he gained a form not unlike Marvel's Sandman-- a being comprised of small grains which he can manipulate in a variety of ways.
Accelerated Healing: Grunge possesses an extreme ability to heal himself. In the first mini series his arm can be seen being shattered, but shortly thereafter, it comes back together. He has been shot repeatedly and the bullets were rejected from his body. He seems to have a remarkable healing capacity, but a reason for this is never addressed. One theory is that he bonds with the embedded bullets, an ability shown when he was able to pass through a wall.
Grunge is also a skilled martial artist and has a photographic memory.