+ Radeka is the real threat , she cast strong spells that can easily break your magic armors and CC you or potentially two-shot you. So having magic shields up for your front-line fighters is recommended.
+ Break the chain and position your ranged on high ground pre-battle.
+ Try creating Oil below her just before the fight , i started the battle so fast that my fossil strike animation didnt finish yet. If you manage to do that, she will be slowed , giving you the advantage.
+ The rest of her minions are weak to magic in general , so if you got atleast one mage in your team , you should be fine at CC-ing them.
------------------------------------------------------------ Bishop Alexandar and Voidwoken Drillworm
+ Let your fighter ( or tankiest character ) go in first and engage a conversation with Bishop. The rest can freely move into position you prefer for the battle. Backline on highground and other fighter near key threat of the battle.
+ Start the battle with your strongest attack then go back to talking. Do that they will start with a dead or atleast injured magister and Alexandar will be pushed back to the next turn , giving you a full round to gang up on him with the other 3 companions. He's the key threat of that battle.
+ Once hes down , focus next on the enemies rogue/ranger or mage. The warrior and gheist are just bruiser and tank , although dont get your armor too low or they may knock you down.
+ When there are only ~3 enemies left , the Void Worm will come up. Thats when you focus on the worm , because the magisters usually change aggro and gang up on it.
+ They probably recognize the common threat and temporarily ceasefire with you. You can still hit them in thier back if you want to though..they are going to die anw.
+ It seem the worm only deal magic damage and true damage (ignore armor) so healing and magic shield will be good against it. While the major of magisters deal physical damage , only 1 mage so physical armor will be useful against them.
Quicklook at the used gears/skills build at the end of both videos.