The thralls consume blood packs to survive.
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.

Tips & Strategies from the iOS and Android app
To unposses press square or x on console:p
I've found that putting a Thrall into any of its helper modes and then leaving the area, they immediately stop working. Coming back you have to cryo them and then set them to it again before they start. This is the same for logging off and back on. This has to be a bug…
I've found that putting a Thrall into any of its helper modes and then leaving the area, they immediately stop working. Coming back you have to cryo them and then set them to it again before they start. This is the same for logging off and back on. This has to be a bug, because otherwise they're more headache than they are worth.
To tame you have to complete missions that have a vault involved
Thralls can gather resources for you if you make them
Capabilities & Carrying
Carryable By
0/12ChartCarryable By
0/7ChartAffected By
2/7ChartCan Damage
0/6Chart
Thatch
Wood
Adobe
Stone
Metal
Tek
Fits Through
0/6Chart
Doorframe
Double Door
Dinosaur Gateway
Behemoth Dinosaur Gateway
Hatchframe
Giant Hatchframe
Translations: スロール, Træl, Esclavo, Servitude, Schiavo, 노예, Boeien, Тралл, Köle, 失落者, 失落者.