A being with no time in it, who eats universes, and who is beaten by a man willing to die in front of him indefinitely.
Dormammu absorbs universes into the Dark Dimension and turns what lived in them into Mindless Ones. His zealots on Earth mistake this for a gift, which is the film’s argument about how a promise of eternal life is usually sold.
He is defeated by the only method that could work on something with no time: a loop. Strange arrives, dies, arrives again, and keeps arriving until the thing that cannot be killed discovers it can be bored. It remains the only fight in this catalogue won by refusing to stop losing.