The main reason You Chen had stayed in Notting City all this time was to make Bibi Dong believe that he was "well-behaved," carving out a peaceful period of growth for himself right after he had just acquired the system.
His influence on Xiao Wu and Tang San was merely a casual move played on the side.
Now that his wings were gradually growing and he was likely to draw extra attention from Bibi Dong, it was naturally time for him to leave.
Chapter 116