<No System, no cheats, no harem. Mind the details. The author takes suggestions, and the story leans toward wish fulfillment>
Sun Wukong... this story has little to do with him.
Do you know how many sworn brothers he had?
The sixth one is the subject of this book's speculation about him.
[I'm another monkey, but I have my reasons for causing havoc in Heaven too.]
At the time this story takes place, the Monkey King has probably just gone up to Heaven to become the Keeper of the Heavenly Horses.
In a small city, a little demon lies low among humans. He can't remember many things, but he feels he must have an important mission.
This imagined story is why the Seven Sages later swore brotherhood, why the Monkey King led the charge through the middle lane when he wreaked havoc in Heaven, and why the King of the Macaque Demons snuck off to take the tower in the bottom lane.