It seemed that the Lich was working hard. He knew that he could try to disobey Jason if he were to get stronger, so he probably would try to recover his freedom at some point.
When Jason reached the troll's territory, he found a bunch of corpses along the way. Jason recalled the situation down south… the morons there probably would need some help since more dungeons are showing up. Jason couldn't go there yet since he would be the sole target of a bunch of dungeon bosses… he needed to obtain all the power that he could obtain in that area before facing those guys again.
"I can't mess up. Once the battle starts, there is no room for failure," Jason thought. "To speed things up, I guess I will deal with the giants and leave the trolls to the Lich. Once he is done here, he will be at level fifty, and then I will send him south. Any more help than that, and those guys will get used to it."