PK tips breakdown for newer players

Nepisce: wrong greater shield. slime stops entwine, you can word out of entwine or zap/brandish out of it if you're deafened by mace. use shield of electricity to make his metal maces prog. if he swaps to non-metal maces, use shield of waves.

wrong dps spell: iceshards is resisted by duergar (they resist cold at 20% reduction). use engulf instead if you have it.

rain of stone is a great choice. good job

dispel magic is a great choice, good job

adhesive web is really good, you can consider using it. likewise grease would make him unable to swap weapons effectively, especially if his dex is below max from web.

Overall this wasn't a fight you were gonna win based on your hp and his svspell. Your best choice probably was to land dispel rain grease web flare then leave and let your allies hit him now he's wounded and has lingering effects to deal with