Chthon

The first Black magician on Earth was Chthon, one of the Elder Gods. The Elder Gods turned into demons and began battling one another for dominance after roving the Earth for a billion years. Gaea gave birth to Atum, also known as Demogorge the God-Eater, in order to defend the nascent life that was forming on Earth.

Chthon built the Flickering Reals, an other dimension, in order to survive. He wrote the Darkhold before he left, an unbreakable book that would bind his dimension to Earth if he ever wanted to make a comeback (introduced in Multiverse of Madness). He has the ability to influence Darkhold users and persuade them to do what he wants.

Many of the creatures that are shown in Marvel were designed by him. His attempt to use Wanda Maximoff as a means of transportation back to Earth went horribly wrong. In doing so, she created a new seal that would keep the Elder god from ever emerging as long as she lived, giving her the ability to fight and consume him.

He is one of the most powerful Marvel gods. In addition to having mastered Chaos and Dark magic, he also possesses telepathic abilities that allow him to read and manipulate people's minds and ritually possess living things. He is very smart, and Doctor Strange is one of the few sorcerers who can fend off the Darkhold's mental captivity.

Fortunately for the Marvel world, this all-powerful being has certain flaws, like his dependence on a live vessel as his host in many realms, the True Darkhold, Wundagore Mountain, Eldritch magic, and others.

Nickname: planet's first master of black magic

Creator: Marv Wolfman, Bill Mantlo