An update on the official wiki, Curtis Johnson is the dev who had a big part in designing Mallyx. Karlos is the same Karlos who posted on this very thread
You can read the whole thing here from http://www.wiki.guildwars.com/wiki/T...the_Unyielding
It does appear there is a glitch(1) in the AI for summoning shadows, likely part of modifications to fight the door glitching. (oh the irony) It is actually possible even now to have him not cast summoning shadows at all during the fight in the room, which is how we tested him(2). I'll want to talk to a few people before telling how since it could be (a) a spoiler and (b) influenced by how we fix it (btw, not the same as fixed before). I will say the design was not to require a fully targeted team to be built from level 0 to 20 to beat him(3). But He should (does) shake up conventional strategies and be at least tough enough to earn his citadel. (4)
I am curious what the teams trying would estimate his difficulty if he only cast summon on those outside the room. (that's not a hint

just a balance pondering.) (Curtis Johnson 04:37, 2 August 2007 (UTC))
Hmm, Did you browse through that thread and see the amount of builds and attempts actual people tried? It should give you a feel for the problem.
The two methods I am familiar with are Ritualist based and paragon based (since he does little to disrupt either). You can read about the Paragon build in the thread, I have not tried it myself. Here is what we did with the Rit based build:
One Rit with Shelter and Soul Twisting
One secondary Rit with Consume Soul for his spirits
One full time and one part time healer using WoH and the like and not rely on enchats.
The main problem we faced is NOT the use of Summoning Shadows, it the use of Summoning Shadows every 5 seconds. We were all in the room, there were no corpses or any fishy business, we even ran up to him to dissuade him from spamming it. Still, he'd use it every 5-10 seconds and the worst thing is, he forces himself to use it. He hits someonw with Shadow Smash, forcing them to fly away, he feels they are fleeing, so he pulls them back with Summoning Shadows. Just an exercise in frustration. Like one time we had an edict, whomever he starts hittin should stand still and not move at all, and rely on the others for help. That still did not stop Mallyx from using it over and over because each time he'd kick his target away, take a few steps to "chase after him" decide that it's taking too long, and then uses Summoning Shadows.
I can't tell you that we'd kill him for sure if he didn't use it on us if we were all in the room, but I think we'd have a very good shot. --Karlos 04:59, 2 August 2007 (UTC)
Yes i read through most of the thread(5) before I even went to check code so i knew what i was looking for. Constant interruption of the entire team at once is not an intended or fun behavior.(Curtis Johnson 06:20, 2 August 2007 (UTC))
I'm kinda glad it's confirmed he's bugged in a way(1), just shows i'm not going totally mad. I'd also like to thank Curtis for taking the time to explain the thoughts and being so open about the issues. It's appreciated and refreshing
A few points Curtis made are interesting.
1. When they tested him, they glitched him into not doing summoning shadows - They did not fight him in the room, under full power. (2)
2. Anet did not design Mallyx to be invincible or limited to just one team build (3)
3. He should shake up current tank-nuke-heal thinking. (4)
4. Curtis did not read the entire thread. Since the this thread is quite old, I would hope he goes back and read it all, especially the recent posts since the update(5)
On the basis of these point I suggest Anet completley rework Mallyx from the ground up to meet their stated design objectives, as as currently stands it certainly appears to fail in those terms. The community may be missing a trick, but the sheer amount of testing by high quality players certainly indicates a serious flaw somehow.