Sigma was originally the honorable and selfless leader of the Maverick Hunters, but after his corruption, he became a power-hungry tyrant. Amidst his madness, Sigma was a calculating and intelligent individual, and on more than one occasion, turned allies of X and Zero against them, and instigated many of the most destructive events of the Maverick Wars, including the Earth Crisis. He was proud and typically looked down on others, not hesitating to kill the weak and laughing maniacally at their expense. His previous "protection through aggression" philosophy has mutated into a huge Darwinism complex, believing that anything that is too weak to progress should be annihilated, a la natural selection.