A notably powerful and persistent threat, Dormammu has been a dread presence for Doctor Strange since the Master of the Mystic Arts’ early adventures.

Watch the new installment of Marvel 101 above to learn the important info on Dormammu and why he’s such a dangerous foe for Doctor Strange – and indeed for all of mankind.

For more on Dormammu, check out our Marvel.com reading guide focusing on some of the key appearances for the character, beginning with his debut in STRANGE TALES #126, as Doctor Strange trespasses unto the Dark One’s realm after The Ancient One asks him to deliver a message – but of what nature?

Click here for the Dormammu reading guide!