Worlds-R-Us: The Rift at Ayyadieh

I'm not a fan of the "rightous Christians,
sinful Muslims" vibe of this image but it's
the only depiction of it that I could find.

WARNING: This content has been "inspired by" (i.e. shamelessly ripped off from, then expanded on) the game Lionheart: Legacy of the Crusader from Reflexive Entertainment and Black Isle Studios. 

In the Year of Our Lord 1189, Pope Gregory VIII calls the Third Crusade against the Ayyubid Sultanate, lead by Saladin, who had conquered the holy city of Jerusalem and looked poised to wrestle the entirety of the Holy Land from Christendom. Kings marched to the Holy Land; the situation so dire that even the kings of England and France called a truce in their war to march together to retake the lands from the Saracens.

In 1191, the long and brutal Siege of Acre is broken – the garrison surrenders. King Phillip II of France and King Richard the Lionheart triumphantly march into the city, taking the Muslim garrison into captivity. King Phillip leaves shortly afterwards, having to attend to a succession crisis within France caused by the death of an important duke while on campaign in the crusade. King Richard stays, intending to ransom several thousand prisoners in exchange for money to continue the crusade, important Christian captives held by Saladin, and a piece of the True Cross. Saladin stalls for time; he sends the first instalment of the ransom but draws out further negotiations, likely intending to raise an army to storm Acre and retake the city from the exhausted Christians. His hand forced, King Richard takes his advisers' counsel and ascends to the hill of Ayyadieh, in full sight of nearby Saracen encampments, and slaughters over three thousand Muslim captives.

In our world, the crusade continued on, resulting in a costly campaign for the Christians that ended with a treaty providing unarmed Christian pilgrims with the right to enter Jerusalem free from hassle or toll. This didn't succeed in ending the contention over the Holy Land, and the disastrous Fourth Crusade begun merely ten years later, resulting in the infamous Sack of Constantinople.

But what if the massacre unleashed something otherwordly?

World-R-Us: Alexandria

Alexander the Great conquers Greece, Asia Minor, the Levant, Egypt, Mesopotamia, Persia and Parthia, all the way to the Hindu Kush. He is forced to abort his invasion of India after a revolt of his troops, so returns to Babylon to recover and draw plans to advance into Arabia as a prelude to conquering India and beyond in pursuit of the ends of the world. In our world, Alexander the Great died in Babylon, his plans incomplete. Whether the cause was illness or poison is still unknown. Alexander's death left his empire fractured and decentralised, the task of nation-building the conquered lands left unfinished as the Diadochi fought over the remnants of what might've been a great empire.

But what if Alexander hadn't died?