"You can see it, can't you. This is your fate. Your friends will turn on you, seeing you for the monster you will become. They will destroy you, Harbinger of Chaos. It's just like the Lady Bone Demon said. Despite your efforts, all you'll ever do is cause pain and suffering."

"The hero and the warrior were like the sun and the moon, their light a protective glow shining upon the world. Together, there was nothing that could stop the two of them, either in the celestial realms, or on earth.
As time went on, the hero gained power beyond comprehension. As the hero's light grew, so too did his shadow, and soon, the warrior was cast in that shadow. In the darkness, the warrior was forgotten by the hero."

"You saw a story about a hero who got handed everything, who didn't have to work for anything, and you thought you were the other guy? The second the hero got real power, he couldn't care less about his friends. That's you, bud."

"Ignoring all of the world's problems"

-----

Options of what could/will happen:

1: Wukong pattern - MK gains power to make the world a better place for his friends, but in the process loses sight of why he did it (cite A Lifetime of Mistakes), and "forgets" his friends. He "was handed everything".
Apparently he was overtaken by darkness, at least in the beginning (as opposed to his friends).
"In the darkness, the warrior was forgotten by the hero."
"The second the hero got real power, he couldn't care less about his friends."
This is what Macaque was trying to make MK believe, at the same time MK believed that he was the wrong Successor.

1.5: non-Wukong vs Macaque pattern - MK leaves his friends (probably only because he would probably turn evil or go insane or something) so they turn on him for it. (Probably reading into it too much.)

1.5.5: Historic Wukong vs non-Macaque pattern: MK has to kill his friends because they turned evil.
Maybe he didn't mean to kill them. We could only know for sure if we knew exactly what happened between Wukong and Macaque.
This is reading a bit too much into Macaque's point in Shadow Play and you have to stick with his original purpose. History will not necessarily repeat itself... Or is it?

2: The Harbinger of Chaos Destiny - Combined with what Macaque said, MK will become some sort of monster. Maybe this means he will forget about his friends because of his power, or he somehow turns evil or becomes corrupted, most likely tying in to his mental health.
I'm this scenario he IS the Macaque, the evil one, the Shadow. He will be destroyed. They will have to, though it pains them.

Which one is he more? Wukong or Macaque?
According to Macaque (and also most likely) he is the 2nd Wukong.
But depending upon the origins of Macaque, it is very likely that he IS the 2nd Shadow and will end up corrupting and being destroyed for one reason or another, fulfilling the HoC Destiny. Especially if Mac trained under Wukong. But that would mean that MK would have to be forgotten by Wukong... Or does it?

Where does history repeat?

Not really anytime...

Except there IS drama between Wukong and the celestial realm and underworld. They're coming for him.