Knowing that his thoughts, actions, and everything about him were controlled, Xiao was beyond pissed, even more with the fact that he had even thoughts of not using his knowledge so as to not affect the 'plot'. Why shouldn't he use his advantages for himself? It's not like the 'characters' are his friends or something.
He will take what he wants, and he will mess up this 'plot'. The ones who controlled him didn't want him to mess with the flow of the true 'story,' and Xiao had only one thing to say to those guys...
Fuck Off!!
If he does this, that 'guy' might get weaker. Maybe he might even die, but what does that have to do with him? So what if only the 'main character' could deal with the issues of the future? Was he Xiao to obediently place his fate in the hands of some stranger? Was he like some obedient dog to run behind the 'plot' and make sure no changes happened?
'Hehehe...you want balance? You want to make sure that I won't go overboard?'