Playing Sekhema with a blood mage seems to eat into allies' honour

Playing with my 2 brothers last night, one was a Witch Hunter and the other was a Blood Mage.

We got up to Zarokh, and suddenly our honour was being drained incredibly quickly even though we hadn't been hit by him. When the blood mage died, all of a sudden our honour wasn't being drained.

We suspect it's because the witch hunter's skills use life, and somehow it was draining our honour. Because after that it was much more manageable.