The Triune Bugged?

I've been trying to do the Triune Uberquest for a while now.
The boss doesn't seem to take damage, even when right in front of the Messenger (check footage). This is just one of many, many times where they attack each other in melee range and nothing happens. I can add more videos if you want, I just happen to record this one. I also tried to add some damage source inbetween them, with no success. Am I supposed to do something in particular for the boss to be damaged?

And I am not sure if this is intended or not, but the boss targetting system is terrible to say the least. His target doesn't change when it gets charmed and it will walk towards its target to attack it until it reaches it, even if it is its ally. Its target refresh period should be a lot quicker.

The idea behind that uberquest is great, but making it so AI dependent, luck based (to not get random bats) and buggy (boss not getting damaged) just ruins it for me...

The charm tome provides aura that allows fatty to be damaged, if you die - the aura is gone. To fix it you need to "reequip" the charm.

Thanks a lot.

But how is a player supposed to know that?

This is the charm description (Dire Charm is the curse you use on him):

And this is what the docs says about the boss:
"To defeat Arihan, High Priest of the Triune, you must find a way to convince him to fight Primus' Messenger, a strange being sent by Drider-King Astrogha. There are rumors of an even queerer creature possessed by the demon-of-deceit Lilith, that could hold the key... "

This should be mentionned somewhere, otherwise it's bad design/bad user-experience...

^ It's mentioned there. Look second row from the top. :mrgreen:

It should be put in red IMO, so easy to miss.

Oh... I still don't understand why an aura is needed in the first but whatever. Thanks.
IMO, it should mention that it gives an aura and it should be mentioned in the white description text rather than putting it in the title.
Item titles are not meant to describe the item, not give instructions.

But I guess that will do for now.

D2 is old and it's hard to achieve cool mechanics without modifying the code. Mechanics will be added to Sigma AFAIK, but for now this is what we have. The 100% Avoid on Arihan is so you will have to Charm him to fight Primus while the aura from Tome of Possession grants -100% Avoid to friendly units. In this case, Arihan has Avoid so you can't kill him yourself with Purify and OW.

Correct, otherwise you could trap him behind some fence and afk farm him.

In this case actually i think its the primus messenger debuff curse (the blue curse that slows you down and locks out ranged skills). I know that when primus casts this, Arihan stopped recieving life degen hit animation even tho primus was clearly hitting him. Not to mention that when primus used this curse and then used the blastwave bat thingy, neither me nor Arihan were teleporting at all untill the curse went off.