How to play:

Drop a "Squad Energy Restore'
Apply status effect
Cast Gloom

Gloom will slow the Lich/Sister by 95%, making them easy to hit
Sonic Boom will strip 100% of their armor
Sonar will cause them to take 14x damage

Enjoy!

(Arcane Healing is optional, if you do need more damage, which you shouldn't, you could use any damage increasing arcane. I prefer Arcane Healing because I don't want to slow the entire team/die if I get hit by a radiation status, and those tend to be the most deadly liches.)
(You can switch [Rolling Guard] for [Adaptation] or even [Redirection] if you want to. I prefer [Rolling Guard] personally.)