I've been doing the quest to protect Zandalor from the creatures coming out of the rifts for 20 minutes now and i can't stop him getting hit, am I missing something?

try drag them away from him and get them to swarm on you i had trouble with this quest at the begining as well

I've tried dragging enemies away but there always seems to be a couple who just ignor me.

i used magic missile to draw them away from Zandalor and then they swarmed me.