Although the Horde Captains possessed strength greater than that of the average Horde beast that Karenssa could create, their intelligence was still very much limited which meant there was no real resistance against Evian's control. However, Karenssa's blood was still within them and it lashed out at Evian's Authority but ultimately bowed its head and allowed its essence to be absorbed, creating an interesting gain;
[You have absorbed 1000 units of Tainted Semi-Eldritch Essence]
''Tainted' I understand must be due to Karenssa's spiritual energy still slightly infused in her blood and her Eldritch constructs but as I have done with souls that had been strengthened with Spiritual energy, I have absorbed it easily and completely made its energy mine.
But... What's Semi-Eldritch Essence?'
[Semi-Eldritch Essence is much greater than Quasi-Eldritch Essence and has climbed closer to being a complete replication of its creator's source energy.