Damaged is a mutant that escaped the bus to sector 21, a facility where the Omega Defiance experiments on people to "advance them". He is not the only mutant the Omega Defiance created. Several other mutants escaped as well. He vowed to destroy the Omega Defiance and then the world. To ensure victory, he personally killed it's members (Helix, General Cross, Xero, etc.). Dr. Necros was the last one left. When Aaron Stone brought him in for questioning he said to Necros "I wish whoever did this would have done it earlier". Necros replied "You don't know what your talking about boy, the monsters that escaped from that bus will be the downfall of mankind". Damaged has extremley powerful telekinetic abilities and is unlike anything Aaron Stone has ever faced. Their is a slight possibility he is Aaron Stone's father, from the reaction he had when he saw Aaron (but Damaged still attacked him). Another clue is when Aaron showed a picture of his father to the rat mutant in france and the mutant replied "he was a prisoner at sector 21". He wore a tattered goblin mask to cover his face and no one knew about his true identity. Damaged was unmasked and defeated in the series finale " Mutant Rain".
Trivia
He is possibly the most powerful mutant in the series.
His power of telekinesis has only one weakness. He needs to physically see his target/opponent to use his power on them.