Any movie in which Apocalypse is the star attraction absolutely has to depict his origins as En Sabah Nur. En Sabah Nur was born a mutant some 5000 years ago in the Jordanian city of Akkaba, but was abandoned as a baby thanks to his mutation giving him an unnatural appearance (he had grey skin and blue lips). He was rescued by Baal of the Sandstormers - a group of raiders and scavengers - who saw the potential power he possessed and wanted to harness that power for his own use - even slaying some of his own men to protect the youngster's well-being. He named the child En Sabah Nur and raised him as his own. Baal taught his adopted son a "survival of the fittest" philosophy and he became a formidable individual in his own right. This upbringing was a key part of Apocalypse becoming the ruthless villain he turned out to be and simply must be shown in the movie. Major spoiler alert (press "next" to avoid it)... Indeed, En Sabah Nur is shown being worshipped in the post-credits scene of X-Men: Days of Future Past (which we know thanks to leaks) and, as such, this inclusion seems a shoe-in.
