Did you know... (NOTE: spoilerific for Watcher's Keep)

Maurvir

that the ritual scroll you get from the Helmite ghost at WK has an expiration date? I didn't.

I wrapped up the whole of WK except for the very last step - choosing how to end the story. I had both scrolls, and since I wanted to use the keep as a storehouse, I thought (stupidly) that I would just hold onto them until ToB - not realizing that you can still access the upper sections of the keep even after using the scroll.

So, I get to the part where I am casually moving all of my party's stuff from the stronghold to the keep and, I notice a message saying that Odren's ritual scroll had disintegrated into dust, but I hadn't planned on using it anyway - I only needed the second scroll.

Right about that time, Aerie decides she is fatigued, and since we never get attacked at the keep, I hit the rest button. Amazingly, despite Meck standing right there, we were able to rest. When we woke up, however, we had a bit of a surprise. The imprisoned one shows up and wrecks the party like it's the end of the world. Being completely unprepared, I did the only thing I could do, and reloaded the last quick save. I figured I would just seal the place and be done with it.

Except it wasn't just Odren's scroll that disintegrated. It was BOTH of them. This was not good, and there was no way I was going to redo weeks of work elsewhere, so I... looked up the item code for the helmite ghost's scroll and consoled it in. (It's plot01q for the curious)

Amazingly, it worked. We got the XP, the lower level was sealed, and, thankfully, the upper levels were not. I was able to transfer the party's stuff to the cabinets in the room with Lum's machine.

All that to say, sometimes the sense of urgency is fake, but sometimes it's not.

Also, as an aside, what do you have to do to kill that thing? He was dropping so many high-level enemies right and left that we never could get a single hit in. I don't think Melissan was that bad.

ilduderino

That is interesting, I had no idea. I’m sure I have taken months in game to finish the keep.

He is very tough to beat, he falls to high level traps very easily (so much so you don’t actually have to fight him as they can completely take him out) and the damage done by Keldorn’s default weapon (attacker takes 5 damage per hit on Keldorn) helps if you keep Keldorn in good shape and he takes the aggro

BrightL1ghts

I've managed to defeat him recently on my solo sorc run with full scs installation. I found this to be a semi-reliable way to defeat him, but still would use a scroll in a no-reload run
(It's semi-reliable because i don't know the exact conditions under which he summons 5 glabrezu (or merilith's on vanilla) and regains his magic resist back)
Spoiler ahead

This strategy assumes you are an arcane spellcaster of lvl 20 +, already got boots of speed(very important), robe of vecna and amulet of power(both are very important), who wants to kill demogorgon in a fair fight without stacking skull traps.

Preparations:
CC 3x ADHW on closest enemy when enemy spotted
Spell Trigger : 3xPierce Magic
Spell Sequencer : 3x Skull Trap
Prebuff : Stoneskin, Resist Fire, PfME (or minor GoI, or GoI and yes it's important to have one of these), Improved Invis (mostly for an extra +4 to all saves), Spirit armor, Haste(very important)

Now, make sure to put auto-pause on spell cast in options.
Before talking to Demogorgon(or triggering his dialogue) cast improved alacrity, and instantly PfMW after that.
Then instantly trigger his speech and force him to "show his true form".
When he spawns, wait just a bit to let him trigger his spell/ combat protections, or you will waste your Spell Trigger and will be forced to reload.
As soon as he triggers his spell protections throw a Spell Trigger at him. CC has a decent delay before it triggers, so your Spell trigger will most likely hit before your CC will trigger.
Now he will will most likely throw storm of vengeance.
That's why you need haste + boots of speed, you can simply outrun this.
As soon as you will see your 3x ADHW from CC, throw a greater malison at him and start throwing skull traps. Since you are still under PfMW and improved alacrity with auto-pause on spell cast, you will have 0 problems with unloading all your skull traps in no time. If It's still not enough, throw a spell sequencer. And that's it.
It may look complicated at first, but in reality all this will happen in like 1 - 2 rounds. Now the only way how you can fail is when he decides to randomly summon glabrezu's(meriliths in vanilla) and regains his MR before your 3xADHW hits him.

Maurvir

In this case, though, he showed up outside the keep and immediately spawned four marileths. Those actually went down fairly quickly with Abi-Dalzim’s Horrid Wilting. However, as soon as they were down, he brought in *six* glabrezu's at a time. I was able to distract them temporary with a deva and Mazzy with the FoA, but my PC kept getting killed with a gaze attack while casting lower resistance. Nothing else was touching him.

Come to think of it, though, I never use spell triggers and sequencers when I should, so maybe I should replay this bit and use them. Good tips!

ThacoBell

He has a bunch of spell protections that he refreashes occasionally. Spell strike wands and the like are super helpful. I also find that leaving one Marileth alilve helps immensely. He won't summon any Glabrezu until every Marilith is dead.

gorgonzola

I find that if the party is strong enough to survive the marileths and glabrezus are a fantastic source of xp, with the right tactics and party composition is possible to farm almost infinite xp from the battle.
once i started it in soa chap 2 and had my 6 people party reach the tob level cap before killing the boss.
if the party has problems to win the battle probably there is something wrong in the party composition, tactic used or level at with you try.