Zamorak (Runescape); used chaos magic to corrupt land into a vast wilderness.
Gabriel Belmont/Dracula (Castlevania: Lords of Shadow)
Discord (My Little Pony: Friendship is Magic) is the Master of Chaos.
With a mere fraction of Chthon's power, the Scarlet Witch (Marvel) could warp all of reality, casting her spells over countless souls, worlds, and dimensions, affecting alternate realities and permanently shifting all the possible futures of the entire Marvel Universe.
The wild and world-destroying potential of chaotic magic and Chthon (Marvel) himself.
Chthon's (Marvel) true form
Gabriel Belmont/Dracula (Castlevania: Lords of Shadow) utilizes Chaos magic via his Chaos Claws.