My last lich playthrough was as undead bloodline sorc. There’s a lich spell that raises enemies killed while under its effect, but they can’t follow you into the world map.

It’s really useful in the longer dungeons but was a complete mess in act 4, since every part of that except the camp and the final dungeon are one location. I was raising every large enemy I killed. After clearing out the flesh markets, I had a large enough blob that they could do all the killing for me with occasional negative energy healing from Staunton.