The Tribunal main quest is HARD from an emotional standpoint, if you're playing a True Believer. I knew the outcome ahead of time, and I really did not want to finish it, because I knew it would absolutely shatter my character. I ended up giving an entirely improvised speech, aloud, which ran about five minutes. Yes, I stood there and declaimed a eulogy at my TV set. I have no shame. I roleplayed my character as a broken person after Tribunal, and retired her to her House stronghold. Then she set off on a top secret mission, allegedly to Akavir, and has never been heard from since. Hmmm....
:D Yeah, my soon-to-be-Archcanon is soon going to experience the same dilemma with Almalexia. I think he just quits serving Her at some point; I actually don't have any goals for him at that stage anymore, other than getting http://www.uesp.net/wiki/Tribunal:Eno_Romari! <3_<3 Just how cool would that look like when worn by Patriarch!
The guy is easy to slaughter in the middle of the street like it; he's the worst sort of heretic known to man, he deserves it. Then my character just takes the jacket, and, uhm, cleanses it off his dark influence or something. Probably a minor Restoration enchantment might do the trick. At least it would make it shine!
Yeah, well, he might just go back to Almalexia and say out this Eno Romari's utterly disgusting beliefs. IIRC Almalexia will say that she will handle Eno later (which will actually never happen in the game). Then my guy is like, '[censored], well, I killed him already.' Almalexia understands and forgives, but my character can't live with himself anymore, defying his God this way, even when it was unintentional. So he retires to his chambers in Vivec, feeling unworthy to ever again serve Almalexia. (Which would basically leave Her alive, stop the 3rd Era from ending, etc.) Yeah, sounds like a plan...
Anyway, that impatient temple servant could work. There have been one or two believers in real life that have done some insane things in their fate or some ecstacy stage, dunno. How about such granting him/her some temporary supernatural-like powers just like that, to destroy Dagoth.