norn quest
populationcontrol
in that one quest for gaining norn as allies "one portal too" far or whatever when you have to destroy the gate destroyers spawn out of do i need to get bear allies to destroy it or can i do it by myself/henchmen do it? jst want to know before i try it again.
Toutatis
You can target the gate just like any monster. Just target it and attack it until its health bar hits zero 
populationcontrol
so i dont need the alies to kill it, just me and henchies?
Toutatis
I've found that the Norn allies during that quest are generally kept busy by the Destroyers that keep spawning through the gate. I've been able to take out the gate and complete the quest with just myself and the henchies focusing on the gate while Olaf and Co watch my back.
Crom The Pale
When you do the quest the norn are with you and they self res so its likely they will be there and killing the gate at the end.
If you enter the dungeon without the quest or on another quest you will not be able to access the final room with the gate, in that sense they are mandatory.
If you enter the dungeon without the quest or on another quest you will not be able to access the final room with the gate, in that sense they are mandatory.