I was counting on Mazao being able to lock onto the identity of the hostile Impermanence through the skull of the Divine Spear, and at the same time, I didn't put all the pressure of this task on her shoulders. The backup plan hidden on Lu Chan was the direction of my efforts.
During the final battle at the old stronghold of the Human Bureau, when I had the other two demon hunters take Lu Chan back, it wasn't just a casual comment made to go along with the mood. I also had the intention of tracking him afterward. Even if I hadn't said anything, Lu Chan would have been taken back anyway, and I secretly planted a thermal energy marker inside his body.