Yang Kai should have personally vetted every person sent into the illusion small world. I wouldn't trust the judgement of those great emperors or their sects. Yang Kai has encountered so many utter pieces of shit from their sects, in high positions, that probably the majority of candidates they would send are good for nothing arrogant bastards. Yang Kai should put them through a little test, to watch how they behave in the company of lower level cultivators in seemingly random situation they aren't prepared for. If they act like stupid tyrants, just send them immediately back home.