I was thinking abt my Quest for the Furnace fic and was also listening to Warrior of the Mind from EPIC and came up with a solid backstory for how Mac's Apprentice ended up as his apprentice so I'm just gonna spit that out here lol
So when Mac is first introduced, he does his big shadow clone monster thing, does some epic flips and shit and defeats his own monster ALL just to impress MK and make MK want to be his student
So how about if that was Mac's second/back up plan for in case YOU (the reader/Mac's apprentice) failed
Mac heard you fighting some demons in an alleyway one day. They were accosting you and you totally beat their asses, which is very impressive for a magicless human
Whether you fought valiantly or cowardly, you still beat them and Mac sees that special spark of potential in your eyes and decides right there on the spot that 'yeah.. that one's coming home with me'
His plan is to train YOU to fight MK, instead of fighting him himself. Preferably a younger looking person so if Wukong appears, it would be a little harder to stomach the fight than if it was just Macaque
And in the beginning, you're a GREAT student. Even if you're a too timid, or too reckless, you're picking up the material quickly, and even when he beats you down, you always get back on your feet
Shadow Magic comes naturally to you as well. Slipping into the shadows, creating clones and weapons, etc. He honestly doesnt know how he got so lucky with how perfect of a student you are.
You're empathetic enough too, so that when Macaque spins up a tragic backstory about how Sun Wukong betrayed him (which is technically not entirely wrong), you feel angry on his behalf and agree to help defeat him.
Eventually you're a pretty good warrior. Even in such a short time frame, you can now kick some serious ass and Mac decides that it's time. You and him slide into the shadows and he takes you to Pigsy's Noodles under the dark of the night.
From the window, he points MK out to you and reveals that he is Sun Wukong's apprentice. The apprentice of his sworn enemy, and in the future, you will have to fight him alone. Once MK is defeated, you both will steal the golden cudgel and fight Sun Wukong together.
You agree emphatically, and thus begin your most rigorous training yet, while also keeping a personal eye on MK. Mac is so proud. What a good student he has. So strong, and smart and sympathetic to his pain and suffering at the hands of the evil Monkey King.
Eventually, the big day comes and Mac sits back and enjoys the show as you and MK go head to head. Since Mac's training has been to vigorous and brutal, you are far more durable and battle-savvy than your opponent and you eventually (decently quickly) manage to pin him down.
You stare down at the Monkie Kid, his staff fallen somewhere unseen as he gasps and splutters, the hard blow to his chest making it hard to breath. Blood drips from his nose and down his chin, and he squints up at you, almost looking as if he might cry.
He is scared of.. you...
He is scared of you.
the realisation is sobering, and you freeze in place, your own staff held over your head mid swing. You can feel warm, thick liquid coating your fingers and you know is it blood. His blood.
Macaque told you to kill him.. but can you really do it? Even if it was for your mentor's justice, can you truly end his life?
Mac sees this and understands your hesitance. He appears behind you, his own claws curling around yours over your weapon. He speaks reassurances into your ear, but each word only makes the chills that run down your spine even colder.
His first time killing was hard too, but you'll get used to it.
He knows its hard, but he needs to die
This is all to defeat Wukong, remember?
... the shadows staff dissipates into smoke and your hands clench into fists. Mac is silent behind you as you lower your hands slowly. MK is barely conscious, but he still stares up at you, breath ragged and wet with blood.
Wukong will be coming any minute.
Macaque is disappointed.
The both of you drop down into shadows and disappear, just in time as Wukong slams down next to MK.... it's silent in the dojo and neither of you can bare to look at the other....
Mac stays silent for a long time, before his voice rings out in the darkness of the dojo.
You couldn't do it, you say quietly, hoping to placate the anger your mentor must feel. You couldn't become a murderer like that.
Get out.
Its hurts to leave the place that has become a home to you, but who knows what he'll do if you stay, so you slide into the darkness and disappear...