This build is for the people, who don't like playing Banshee and don't wanna invest any forma. Granted, this is quite endgame price-vise, but if you're looking for killing liches/sisters - it's just what you need.

Panzer Vulpaphyla with Synth Fiber + Synth Deconstruct required. Change out Arcane Fury for something else, if you do not intend to use melee.

Playstyle - shoot or hit with any weapon to proc Growing Power > use Gloom > Sonar for damage, Silence for survival. Run around killing everything, that is staggered, have great energy efficency because of Equilibrium and Arcane Energize, survivability with 87% slow on gloom, high damage with 12x multiplier.
The only thing is that against high levels this is much slower, then what you can do with different builds or frames, but this is the best lich/sister killer for now.