The Marvel Cinematic Universe's current major villain, Kang the Conqueror, was originally Nathaniel Richards, a young man with a destiny to become one of the deadliest characters in Marvel's history. Richards gained a taste for conquest after traveling through time to 2960 BC, where he used future technology to aid him in taking over Ancient Egypt. He ruled over the land as Pharaoh Rama-Tut, establishing a firm base of power before coming into confrontation with time-traveling heroes of the Marvel Universe including the Avengers, Doctor Strange, and the Fantastic Four. Existing before eventually evolving into both Kang and Immortus, this version of the character is deceptively most dangerous, due to his inexperience and tendency to alter the future without any consideration of the consequences.
As the first incarnation of Kang introduced in the Marvel Universe, Rama-Tut first debuted in 1963's Fantastic Four #19 (by Stan Lee and Jack Kirby). Originally a historian from the 30th century, the man who became Rama-Tut was bored with living in a peaceful society and used time-travel technology to journey to the past and conquer Ancient Egypt. Armed with knowledge of the future, Rama-Tut's goal was retroactively stated to be finding En Sabah Nur, the young mutant who would one day become Apocalypse, and raise him as his heir.
Rama-Tut's Plans in Ancient Egypt Backfired
Rama-Tut was later revealed to be Nathaniel Richards, a descendant of Reed Richards. At this stage of his life, Rama-Tut had not yet become Kang the Conqueror or Immortus. Instead, he was merely focused on his kingdom, one that he had taken over with technology that literally drained the willpower of Egypt's people. But Rama-Tut's time as the Pharaoh from the Future had dire consequences for the rest of the world.
His quest to find a young En Sabah Nur was thwarted early on, as his most trusted scientist, Logos, had hidden En Sabah Nur among Rama-Tut's slaves, foiling a key aspect of the future conqueror's plans right under his nose. When Rama-Tut discovered this, he killed Logos and then made an offer to En Sabah Nur to be his heir. Angered by what the pharaoh had done to his protector, En Sabah Nur rejected his proposal and unlocked his powers, becoming Apocalypse and forcing Rama-Tut to flee while the enraged mutant decimated his army (as depicted in Terry Kavanagh, James Felder and Adam Pollina's 1996 Rise of Apocalypse miniseries).
The Unpredictability of Rama-Tut Makes Him Dangerous
Rama-Tut's impulsiveness and unpredictability make him much more dangerous than his later iterations. Kang developed a taste for battle and conquest that engulfed entire galaxies, but by the time he took up the title of Conqueror, he was a seasoned warrior who knew precisely what he was doing with regard to how his actions would affect the timestream. Likewise, the battle-weary Immortus is older than both Rama-Tut and Kang and has an even greater understanding of time-travel as a result. While Rama-Tut shares those ambitions, he has none of these more refined qualities.
His desire to go to the ancient past armed with future knowledge and weaponry was the result of an almost childish obsession. He loved Egypt's ancient culture, so he subjugated it for himself. Rama-Tut tried to operate with a plan, but it backfired. His goal to have En Sabah Nur as his heir instead resulted in the origin of one the most dangerous mutants in the history of the Marvel Universe, one who would develop a hatred for humanity partly because of Rama-Tut's cruelty.
Rama-Tut is a time traveler who genuinely doesn't consider the consequences of his actions. And it is the rest of the world that suffered those consequences while he simply departed from the time period tainted by his touch.