In the audio commentary for Doctor Strange in the Multiverse of Madness, Sam Raimi revealed that Wanda was going to have Mordo decapitate himself (via Digital Spy). The film’s storyboard artist Jeremy Simser backed this up with some drawings published on his Instagram Account. A four-image storyboard shows Wanda holding Mordo’s decapitated head against a backdrop of mountains.
Raimi said that this scene would be the start of Doctor Strange 2, as opposed to the multiverse chase with Stephen Strange (Benedict Cumberbatch) and America Chavez (Zochitl Gomez). “[616 Mordo] went after the Scarlet Witch to take her power because he knew she was dark and horribly corrupted by the Darkhold and she killed him, cut off his head and presented her to Strange in a later scene. It was a really great script, but it slowed the start too much, so we had to lose it,” Raimi revealed (via Straight).
Deleted scenes and script rewrites are non-canon, so both Mordos we’ve met on the big screen are safe for now. Whether we will see a reprise of the role of Chiwetel Ejiofor remains to be seen.