Confessor's Stronghold
This story instance is designed for multiple players. It can be (and does get) soloed; it just takes being more careful.
In the early part of the instance, you have to take control of the first platform. There’s about half a dozen initial foes, and then there’s a new group that shows up. I believe you can get both groups to overlap under some weird conditions. With a mesmer, I used focus pulls and gravity well to clump them up and then AoE/cleave skills to hurt them.
In the justiciar fight, the support mobs are endless, but you should never have duplicates. Were you actually fighting 100 NPCs at once? (I’ve never seen nor heard of this before) or did you just mean that they kept returning? That is the design. Ignore them; focus on Adrienne.
She does hit very hard and her knockbacks are very frustrating. So, as a mesmer, I’d be taking advantage of blocks (F4, sword 2), stuns (F3, etc), and blink or the stability mantra. You do need to do some damage to her, but if you can keep up some decent phantasms, that shouldn’t be a problem.
That said, your best bet might just be using LFG to find another player to help out. The fights are much, much easier with even just two people.
Good luck and please let us know how you get on.
She has an unbreakable Defiance Bar so stun isn’t going to do much.
The high damage wouldn’t be so bad if not for the additional attack speed as the fight goes on.
On my 12+ runs the adds always respawned so I am not sure where someone got the idea that they did not. Maybe they were referring to a different fight. After the first couple runs it became obvious that fighting anything besides Adrienne was a waste of time.
The stun is to keep the adds from following; it’s not for the justiciar.
The only story instance designed for a party was Migraine mode. All others are actually balanced for solo players. It may be easier with more than 1 player, that doesn’t mean it was designed/balanced for more than 1 player.
The hard hitting attacks from Justiciar Adrienne are pretty well telegraphed. It’s more timing things right that makes or breaks this instance.