>>139614565Several theory as to why the Lich let Simon, Fionna and Cake live:
-Simon posit that after having succeeded in killing all lives, the Lich become purposeless and thus depressed and just didn't had it in him to kill them off.
-an other interpretation is that, being stranded on a lifeless world, there is no food for them to eat and the Lich would rather enjoy seeing them dies slowly of starvation
-the third interpretation is that the Lich, being the last scholar of Golb and Golb being now Betty, as well as Betty's wish for Simon to be safe still being in effect, means that the Lich won't hurt the husbando of his master.
Either way, he now reign on a liveless world now and remain inactive, just sitting, after having succeeded.