Taroceth seems to be bugged. He asked for three corrupted blood, which I provided, then he was attacked by two rangers and the Priestess, who were defeated. He seemed pleased with the result of the battle and advised me to talk to him further. When doing that, however, first he declared himself "occupied" and then (after some more zoning on my part), he went completely dumb.
Here's a screenshot that captures most of the battle and the dialogue.
Here's a screenshot that captures most of the battle and the dialogue.