Location: From the Last Bridge - w n 6w 3s 3w n e 3n 2w n e, d is it's area. You have to walk through mudlled Windswept plains, which eats moves a lot, have some loop and one-way exits (not random, so *follow* given dirs), and whirlwind here can randomly teleport you around.
Strategy: Mormaeg area have web mudlle, which prevents you from leaving the room, and thus causes mobdeath. Web can be burned any fire (natural or magical), but it requires to drench webs with alcohol or oil. There in Mormaeg's area loads lantern - don't forget to get it and check if it's full (try light it)!
There is also instant-dt (scaling steam - so no death cry even), so examine every exit w if you don't have map!
On the half-way to Mormaeg there is one-way exit; after you pass it only way out is kill Mormaeg or die: way out is down from it, and you will be not able to pick it while spider is alive (it tracks).
Kill all mobs (mostly spiders and undeads) on the way. Actually you can skip them (Mormaeg doesn't call it's fellow spiders), but you will just have more place to fight and less breaking concentration hits from lesser mobs. When you enter room s from last spider before Mormaeg, you will see first mudlled room: web will trap you! Have oil or whiskey in inventory, and make short aliases to “pour oil/bottle web”, “burn web” (lantern/torch must be equipped). Both are instant commands, you can do it even while fighting. Remember that new webs will catch you every time you enter mudlled room, so pour and burn it again every time. Then go w and rest full.
Mormaeg is s from this room with one more spider. Buffer must enter and hit Mormaeg (not just spider - it's 2.spider in the room), then nuker enters, burns the web and starts nuking Mormaeg. It is low on hps, and dies in like 5 fballs. You must have remove poison, because buffer will be arachniated for sure. After it's death pick/open crack down, d open board s - and you are on OER near Windswept again.
You can solo it too, in this case thief need brown bottle ready (after last changes it will protect you from re-poison after you remove poison for the first time), and mage must have 5 stored quakes (will not kill Mormaeg, but will get it down to bad, then quickbolts with staff work almost always). And remember: you can't cast in mudlled (web) room even if you already burned web - if you buff Mormaeg! Burn, flee to any other [non-webbed] room and cast there.
Level: hero buffer+hero any class; legend mage; hero thief.
Loads: topaz (in corpse, not always), sable pouch (on the ground).
Mobs unique to the zone: