According to reports, Kang wasn't always meant to be the MCU's main character, and some suspicions concerning Phase 5 & 6's earlier intentions have emerged.
Kang the Conqueror by Jonathan Majors changed the Marvel Cinematic Universe's Multiverse Saga. He Who Remains, Majors' Kang variation, appeared in Loki season 1.
The MCU's Multiverse Saga began with He Who Remains' death, with Majors playing a major role.
The actor debuted Kang the Conqueror in Phase 5's first film, Ant-Man and the Wasp: Quantumania, which established the multiversal Council of Kangs. The Multiverse Saga relies on Majors' Kang, but that wasn't always the case.
Due to Majors' Kang, Marvel altered Phase 5 and 6. The MCU's Phase 5 & 6 were not supposed to include Kang so prominently, according to the new source.
After seeing Majors' riveting performance as He Who Remains in Loki and the initial Ant-Man and the Wasp: Quantumania footage, Marvel changed its mind.
Kang the Conqueror was initially supposed to have a minor role in the Multiverse Saga, hence several theories try to explain how the MCU's multiverse chapter would have played out without Majors' game-changing performances.
The movie, named after one of Marvel Comics' most iconic storylines, is expected to feature several characters from Marvel's live-action history, not just the MCU.