So I have a Mortal Kombat x Assassin's Creed plot bunny attack me. So let me introduce to you, the Prince Desmond AU.
So while early in the pregnancy and technically married (I don't honestly know if it was official given the fact of staying off the records), Kayana Al-Naar is sent to the Mortal Kombat Tournament on Shang Tsung's island (this is in the events of Mortal Kombat 2/ the second tournament part of Mortal Kombat 2011) and isn't doing so well physically speaking. Shao Kahn is present and approaches her almost sensing her condition. When he does reach her she collapses. Shao Kahn recalls his champions and forfeits the tournament. Raiden concerned follows the Kahn to Outworld and is actually shocked that he does have a heart and can be kind. Shao Kahn yells at Raiden for his lack of concern for a pregnant woman and Raiden explains "she's not my champion."
When Kayana wakes up she is surprised. Shang Tsung is tending to her and explains everything. Due to him being forthcoming Kayana explains the truth of her situation. An arranged forced marriage to unite two bloodlines of the Assassin Brotherhood. Shao Kahn is pissed. Over time and with care research they learn Kayana, legally speaking, isn't married. So, with the fact that he's been courting her Kayana agrees to officially marry the Kahn.
The benefits are staggering. For one thing Shao Kahn no longer has to attempt to invade Earthrealm through Mortal Kombat, they are a stable ally through Kayana. Another is that Outworld gets a queen and an heir.
That is then where Kayana asks Shang Tsung for assistance. She has the Prophet's Codex, Kano's sticky fingers lifted it before Daniel Cross could ever get it, and revealed her son's fate.
The sorcerer agrees, knowing he can override enough of the child's DNA in the womb to ensure his claim to the throne cannot be challenged. However troubled by the prochey heads with Ko'tal to Earthrealm and to the Grand Temple. They cannot enter but Minverna and Juno do show themselves. They hear the same thing Desmond will eventually hear. But Minverna gives Shang Tsung a hint as to save Desmond from his fate.
Desmond is born and grows up raised as the beloved prince of Outworld. Shao Kahn is tough on him, but he wants Desmond not just to survive but thrive. To live.
Desmond's lessons are from each of Shao Kahn's inner circle. Ko'tal trains him with blades and as a soldier, Ermac fortifies his mind (making Juno's control of him near impossible in Brotherhood), Erron Black trains him with firearms, Syzoth (Aka Reptile) trains in hand to hand combat, Shang Tsung teaches him magic which Desmond can not do but he can recognize it, Sindel along with Kayana teaches him manners and how to play the deadly court game, and Shao Kahn teaches him how to run the realm. Kayana eventually teaches Desmond the assassin skills at about age five because he has a foundation with the others. He also learns about the brotherhood from his mother.
With help from Outworld scholars, Desmond learns a lot about the history of Outworld, Earthrealm and the Assassin Templar shadow war. At six meets Cassie Cage for the first time, she is also six at the time and they hit it off. Shao Kahn, Kayana, Sonya, and Johnny agree to not push the children but also to not discourage this.
When he turns sixteen however something goes wrong. General Raiko had been unhappy for years and finally had the balls to commit a coup. He used Outworld's Kamidogu Dagger to control Ko'tal and have him "kill" Desmond. Desmond knocks sense into him and they quickly pull a Joseph (well more like his brothers) and dip Desmond's outer coat in blood drawn from a cut Ko'tal made across Desmond's chest, along with giving him his scar.
Desmond flees to Earthrealm, and canon for him procceds as normal.
This is where I am stopping. I will share more if there is interest. Let's say if I get five comments from people asking questions then I will do another post with more.