To be honest it would make sense if that was the case because we are halfway done with season 3 and still nothing about him. It would he a fresh breath of air to the BL community if he stays good till the end and even as someone whose faves are Yawhi and Jooin, I would love it if Cain stayed good till the end. But because we don't know anything about him, his leaves a huge room for the author to be like "ta da, Cain was actually lying all this time, he's actually terrible" becase there will be no previous infor for the fanst to use and be like "no Cain was never bad whyd you ruin his character now" etc etc.