In the main map temple of the loon is giving you the cream of the accursed berserker line , Dalinsia,Sonja,Urlic,etc …
But surges tier 4 are giving you unique fighters too that gain really good stats and they can be considered as die hard thralls.
Then again,high lvl purges are giving you unique thralls as well.

In order not to die until lvl 20 it’s best to use full build authority, final perk well trained.
My method however is not this. I don’t risk my combat efficiency for thralls. I play full agility build , I don’t allow great engagement on my thralls and I don’t take them on npc camps, it’s pointless for their growth,the experience gained there is very low . I don’t take them on surges, I do them alone very efficient or with other players. And this gives me the pass …
Name your server and I’ll join for a week to share info together but above all to have fun fellow exile. You cannot imagine the fun and the power 2 players have against anything in these lands.