When you die, you enter spirit mode, so only holy enemies like paladins can see and attack you. The sprites change to show this.
For now, I'm having trouble with the balance, so you can feel powerful but also threatened. A few skeletons feel worthless, but too many overwhelm the enemy. Maybe I'll give the player a limited number of skeletons? I also want some kind of progression, allowing you to get more powerful over time, but this could be tricky.
I'm also not sure what the course of the game will be. Just one room that gets more and more challenging until you lose? Multiple stages that end when you defeat everyone? Rooms that you move through like a Zelda game? Whatever I go with, I'm not sure I'll have much time for it.
I wonder whether the problem might not stem from a lack of control on the player's part: if I understand correctly, the player controls only the liche, avoiding (and occasionally zapping) enemies and raising skeletons, while the skeletons do the brunt-work of the killing. Perhaps the skeletons would be less problematic if either the player had some degree of control over them, thus inserting an element of skill to their actions, or if their contribution were less powerful, thus giving less impact to their numbers.