Can Consume (combat drain) be used to dominate orcs?
Solution 1:
Provided that Domination is selected as the upgrade for Drain skill, the Consume skill will convert orcs by default. However, this behaviour may be changed by equipment.
In my particular case, a ring (named "Rune of Horrors") had as one of its bonuses:
Consume attacks make enemy heads explode, causing nearby enemies to flee
Removing this ring resulted in the regular Domination behaviour when using Consume.