Chaos (Final Fantasy)

Chaos is the final boss of the original Final Fantasy game. He is an incarnation of Garland occuring 2,000 years prior to the majority of the plot of Final Fantasy. The Warriors of Light travel to the past and discover Garland there. He transforms into Chaos and attacks, but is ultimately defeated.

Final Fantasy XII
Chaos returns as an esper in Final Fantasy 12. He is named Chaos:Walker of the Wheel, and is one of the 8 hidden espers in the game. He bears a resemblance to his original appearance, but has no wings, and sits atop a large floating wheel. He is the only esper to posses multiple elemental attacks.