15 Fantastic Four Villains Who Could Be The Next Big Bad Of The MCU
9. Annihilus
An insectoid creature with a paranoid fear of death, Annihilus attacks and destroys anything he believes threatens his lifespan. Unlike other immortal (or near immortal) beings on this list, Annihilus can be a big bad whose mortality only makes him more dangerous and destructive.
Annihilus is from the Negative Zone, and while the Negative Zone should be present in the MCU, there's another place Annihilus can be tied to: the Microverse.
Although he's not the most powerful Avenger, he's had arguably just as powerful of an impact on the MCU as Tony Stark has. It's a safe bet to assume that Ant-Man and the Wasp 3's story will dive deeper (figuratively and literally) into the Microverse which provides a smooth way to introduce Annihilus.
Subsequent films could bring him out of the Microverse into the main universe. If he senses that the child of Reed and Sue Richards will become a powerful mutant, Annihilus could attempt to abduct the two heroes and imprison them in his home within the Negative Zone.