You can get tamed thralls via the missions in the city
Thrall
Thralls are infected human survivors corrupted by the Red Element in ARK: Lost Colony. These humanoid enemies wield weapons and coordinated tactics, often encountered in fortified strongholds and hostile encounters.
More Thrall Taming & KO Tips
To tame you have to complete missions that have a vault involved
I find them hard to organize into army’s, maybe a feature could be added to make it easier.
So i had a single player valguero world and i decided to ( don't judge me there was no other option) spawn some in and after that i couldnt walk backwards and there were these “invisible walls” so i couldnt get into my own base, very VERY frustrating
A very quick way to tame one is to do a mission with a vault included, but use like a high damaged dealer