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 Comics) 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 Comics) himself.
Chthon's (Marvel Comics) true form
Gabriel Belmont/Dracula (Castlevania: Lords of Shadow) utilizes Chaos magic via his Chaos Claws.
Raven (DC Comics) being the daughter of the demon lord Trigon, is a natural at dark and chaotic magic.