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. They take a temporary break and Grunge travels with Freefall to Los Angeles, where he gets into trouble due to a high win rate. His abilities make it seem as if he and Freefall were statues.
Grunge is a skater/surfer and enjoys spending his afternoons sleeping in. Although he with three beautiful superwomen, only Freefall appreciates him for who he really is. However this never stops Grunge from trying to hit on Caitlin Fairchild constantly, in many maneuvers that sometimes violate her right to privacy. Freefall goes unnoticed, despite her feelings for him and Rainmaker attempts to serve as the voice of reason for Grunge's attitude, going roundly ignored.
Despite his personal history, Grunge is dependable on the battlefield, listening to orders when given and improvising new ways to help. His sound system defeated the villain known as Helmut. When the girls were kidnapped by a toy manufacturer, Grunge used the properties of the toys themselves to help rescue them. After a notable round of cluelessness, Grunge travels to the desert alone and confronts a trickster deity, who puts him through his paces. He is picked up by his friends, who believe he was just hallucinating everything because he did not bring enough water.
The interruption to regular life brought on by super-powers is normalized a bit when Grunge returns to school. He ends up with Caitlin in high level classes due to his photographic memory. His poor choice in new friends almost leads to the loss of old ones, as they do not like Rainmaker's more peaceful worldviews. It does lead to the release of an angry, super-strong simian that had been experimented upon in the school's laboratories.
Grunge's life is interrupted when I.O. forces blow up his house and slay the robotic housemaid. Grunge and friends travel to a small island where Lynch's friend is operating. Unfortunately the island contains a spaceship, which takes Grunge and Caitlin deep into space. There, he is affected by an alien system and goes on a rampage.
Grunge's second trip into space was not so far, only going so far as the moon in order to help out in the Fire and Heaven incident.
After the Worldstorm event, the origins of Grunge were further rebooted. Owing his powers by careful genetic manipulations operated by the hidden Tabula Rasa group, and sharing somehow the soul of the previous iteration of the character, but none of the memories, Grunge lived his younger years as the stereotypical "momma's boy", sickly and nerdy in appearance and mannerism, and even more intelligent than Caitlin. However, when hitting adolescence, Grunge decided he was unhappy with his unpopular, bookish self, and decided to "reinvent himself"; a new constant of his life, adopting a rebellious persona to distance himself from his overprotective mother, and covering his nerdish self with a more easy-going, frat-boy like persona. At that point, Tabula Rasa caught up with him, and he was kidnapped along with the other Gen-active boys. There Grunge, after helping in the escape, became a sort of big brother for his teammates, deeply caring for his new friends, and jokingly being the clown of the Gen 13. His friendly and warm personality earned him the affections of his friends, until he was forced to slay Kid Apollo of the Authoriteens in self-defense, thing that leaves him in a deep state of depression, until Caitlin and Roxy manage to remind him how he acted in self-defense alone, and he always managed to defend his friends. Returning to his old self, but noting how much he was now fearing "the ability to reinvent himself."
During Gen 13's adventures, Grunge was revealed to be, as his Gen 13 teammates, the recipient of the soul of his original namesake, collected by the Doctor and restored in the new body. However, in this life all the Gens exhibit different tendencies, becoming progressively their own persons
After the events of Number of the Beast, Grunge unwillingly absorb the makeup of electric energies, becoming a dis-corporated being: in this guise, he's able to help his friends against a group of scarred humans, resentful against the "capes" that brought ruin and misery in their lives. Grunge and the teens later hitchhike with Archimedes Sin to a skater park, known as Sk8-Gra-La, that is run by teens he entered into a dangerous skateboarding competition and was crowned king. However, he then discovered that his predecessor is to be eaten in a soup. Grunge was saved by the Gens including a new member of Gen 14 Goo.
After fleeing with the resurrected, child-age clones of Megan and Dr. Cross they came into the town of "Malice" that is under the "protection" of the World War II villains, the Fearsmiths. Grunge and his friends were beaten by the villains and were left for dead before being saved by the Paladins, who offered to train them. Grunge trained with Redeemer and equip himself with a utility belt containing elemental pieces for him to absorb which proves useful in future battles.
Grunge and Gen 13 later participated in Earth's battle against the Knights of Khera. After the battle, Grunge decided to stay with the other heroes of Earth who allied with the Wildcats in help repairing Earth, in which he became Spartan's second in command on Skywatch III. During the three month period of Earth's reconstruction, Grunge spied on Team-7, who refused to cooperate with Spartan and decided to help the planet on their own, by using Shift-Door technology and discovered to his shock that John Lynch was planning on awakening the Warguard. He then utilized Shift-Doors in teleporting the Warguard away from Team-7, and onto Skywatch, but only to find that one member of the Warguard was missing.
- Molecular Absorption: 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.
- Accelerated Healing
- Metamorphosis: All or any part of his body can transform into stone, metal, or even gelatin. He has also demonstrated a limited ability to transform other people as well.
- 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.
- Superhuman Durability
- Superhuman Strength
- Photographic Memory
- Martial Arts: He is naturally fit and has brown belts in Aikido, Kempo Karate, Jiu Jitsu, Taekwondo, and Kung Fu.
- Grunge is a fan of the bands White Zombie and the Foo Fighters.
- 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.
- A vocal video game lover with an excess of confidence in his gaming skills, Grunge has none the less been bested at fighting games by Freefall at least twice.
- Grunge has appeared in the following non-WildStorm Image publications: The Deadly Duo Vol. 2 #3.
- 135 Appearances of Percival Edmund Chang (Wildstorm Universe)
- 50 Images featuring Percival Edmund Chang (Wildstorm Universe)
- 9 Quotations by or about Percival Edmund Chang (Wildstorm Universe)
- Character Gallery: Percival Edmund Chang (Wildstorm Universe)