User blog comment:20thCentFopp/The Fantastic Four in Egypt: Why the Fantastic Four are Truly Inept/@comment-24308873-20131212010056/@comment-4652104-20131212145643

I think the two characters were simply rolled into one later. In Avengers in the Celestial Madonna arc. Isn't Immortus also Kang?

If I recall correctly it goes like this: Iron Lad becomes Kang, Kang becomes Rama Tut, Rama Tut becomes Immortus. But since they are time travelers they keep bumping into each other.