Corg is Sera's counterpart in every respect. Both were created simultaneously as the elite children in the Invid's enlightened evolution. Like Sera, Corg is confused by his new emotions, but unlike Sera, feels no sympathy for humans.
Corg uses his emotions to foster hate and revenge. He quickly comes to enjoy the thrill of combat, delighting in challenges. He excels at war and becomes an almost unstoppable killing machine. He is finally killed by the Beta Fighter piloted by Scott Bernard, but only after Corg had nearly killed him and trashed the Alpha in an early battle, immobilized Lancer, toyed with Rand and Rook (playing cat and mouse games, blowing Rand's Alpha apart, limb by limb) and destroyed dozens of other REF veritechs.
NOTE: Corg is definitely blown to smithereens in the final episode of the T.V. series, so there is no way he can return.