Someone asked me how one does this quest, or really any quest, with minimum kills.
It's 20% knowing the mechanics (sources of noise, what does and does not break sneak, knowing of extremely exploitable abilities like Shadow Phase, etc.), 70% your own twitch skills, and just about 10% luck.
There's really no way someone can learn this stuff without a proper demonstration. You can't just go "hey this is a noisemaker, it's a thing in this game, okay now go do it."
Thus:
1:25 this crest is just barely out of reach unless you jump "onto" the crate, which gets you a few pixels closer
1:40 two things can happen here: Slaad are all on your left and you can go upstairs without issue, or they're all blocking the stairs in which case you can use a Noisemaker to move them away, or you can do what I did and forget which piece of geometry can be climbed on
2:16 this room is the first "hard" one. It's all RNG, just be patient and wait for an opening. If you get hit by an Orthon/Bearded, even if it's a dodge/miss/etc, they will aggro on you and not leave you alone; they'll teleport right on top of you, even if you're invised, sneaking with >200 scores and half a dungeon away. You might have to wait until the humans are all dead and then move the devils. Again, just be patient in this room.
3:15 Flaming Sphere is probably not best for this section. I am a fan of them, Saekee, but noisemakers are a lot more predictable. At any rate, to get past this room, and all subsequent rooms like this, the mobs need to be brought into the hallway and then they need to be brought into the next room. This requires two noisemakers, in my experience: the mobs could hear, say, the noisemaker I put down at 3:31, if they had not yet been moved by the Flaming Sphere, but a lot of the times if it's too far away and the mob has not been "intrigued" in any way, they will not move. At any rate, what I did in the video would have worked fine and not required a second noisemaker had I waited about fifteen seconds so that the noisemaker could be active when the sphere was not.
Basic rundown of Flaming Sphere vs. Noisemaker:
Sphere pros:
-very large aggro/investigate area. Mobs will come in from quite a distance, and mobs will come more reliably (with noisemaker, as noted before, sometimes they notice the noise but do not move to it).
-Lasts longer. Sometimes, when a mob has finished investigating a noise, it will move back to its original position. Flaming Sphere delays this.
-does not require Rogue levels
Sphere cons:
-you are kicked out of sneak mode and invis when you use it. You can use Shadow Phase and similar abilities to get around this, but it does mean there is no way to use it in front of See Invis mobs
-it travels towards mobs/moves around in general, meaning you can only predict where mobs will gather when they move to investigate it
-initiates a cooldown on Invis scrolls. I don't think the Broom from Night Revels does this, however.
4:39 I took a big risk here by not moving that Orthon into a better position, but it worked out. You can get closer to a mob than you think, but it's always a gamble. In the event you do get aggro on a teleporting mob, and you don't want to reset or kill the mob, you can get some distance, quit out of your game, log back in, and hopefully you'll be in a position where nothing is aggros on you. It's really cheap, is borderline cheating, but it saves time. Note when you do log back in, you will be invis but not sneaking, do take note of that. Also if you have long load times, the instance might reset before you get back in and you'll be at the quest entrance.
4:55 these devils will not move until you start walking down the hallway. However, if you move too far, the Deneith soldiers behind them will spawn in, and the devils will aggro on them. This will prevent you from moving the Abishai and the devils with one noisemaker, and it will also cause you to have to wait until there's a clear path through the resulting fight.
6:04 these two soldiers are going to get shredded in a few moments, which is a problem because it could move the devils into a bad position. You see how long and narrow this hallway is? If two devils end up in a position where they're blocking the way, you have to pull them a very large distance and it will take a lot of time. Thus, it's important to grab the crest quickly and avoid the fight that occurs at 6:36.
6:12 just a note: if you do not pull the lever in the beginning, this room is incredibly difficult, as it will have something like eight devils who you can't really pull anywhere.
6:50 the cats see invis, and often they get into that aforementioned state where they will notice a noisemaker but not move to it. They are also very slow. Just don't place your noisemakers too far away and don't be too quick/slow with them and you should be fine
8:15 I didn't have to use Shadow Phase here, but it's safer to use it whenever you pull a lever/open a door/etc. If you'll notice, I have five Thunder-forged robes. If you want to be sneaky a lot I recommend getting at least getting two of them. Remember to invis again when phased and do not move.
8:35 Slaads do not teleport and do not see invis so I just phase through them. Sometimes, tumbling through a mob will not aggro it but there isn't a consistent way to pull this off. Shadow Phase will allow you to walk through mobs if you don't have a tumble-through-mobs ability, though it can easily be twisted from Magister Tier 1. At 9:15, you can see that mobs without those special properties will lose interest quickly.
10:00 it is difficult to pull these mobs correctly. The devils will very quickly return to their original positions. The cats see invis, are much slower than the devils and will also return to their original positions. Unlike some mobs which may or may not return to their original position after finishing an investigation, these mobs consistently do it 100% of the time.
10:15 at this moment you can see me checking if I have an "eye". If the eye next to your character when sneaking is present, you are in a mob's cone of vision. Sometimes, their cone goes through geometry that it should not. Be aware of this eye.
11:34 you can see that these mobs start to return to their original position almost immediately after there is no noise to investigate
13:35 Malicia's cone of vision prevents me from checking whether or not the corner is safe (it usually is, but I like checking anyway). I just turn her around with a noisemaker. Unlike the trash, she does not return to her original position.
14:45 bluff doesn't work in EE, the DC's are too high. Assassin's Trick is like bluff but better in every way. Bosses without see-invis will need a few tricks in order for them to get into melee range.
15:48 enjoy fighting Malicia in first-person view while using Deception. She takes up most of your screen. Hopefully your parent/sibling/signifigant other/etc. will not walk in on you.
18:28 SO LONG NERDS