There were several hidden skill checks in the last part of the DLC (or the sound of "Skill check failed"; the Pool of Memories) and after defeating the Porokoa is was possible to tell Engari that the Faces were incarnations of one Watcher (with "Honest" disposition). I could not confirm or disprove it in my playthroughs, because I was not able to pass the above-mentioned skill checks.
Is this information correct? And, if it is, why do the Faces go on a murder rampage, when freed (with or without host)?
I apologize in advance, if the topic was started too early (10 days after the release of the DLC).