Neverwinter Nights: Hordes of the Underdark canon? *spoiler*

Are the events detailed in Hordes of the Underdark canon?

Basically, the drow are attacking Waterdeep through Undermountain, and an ex-adventurer offers a reward to anyone who can make it stop. Enter the PC, who delves into Undermountain, finds out the mad archmage who built it was inprisoned by the drow, releases him, and in return, gets Geased into killing the head of the Drow invasion. You get teleported into the Underdark, and after a bit of adventuring to defeat some of her allies (and gaining some of your own) you go and attack her.

The thing is, during Lolth's absense, she had bound Mephistopheles, Lord of the Eigth to her service, which was why she rose to power so quickly. When you kill her, you free Mephestopheles from her bindings, and he proceeds to build up a nice army to conquer the world, while banishing you to Cania.

Now we get to the relevant bit.

This whole time you were carring an artifact known as the Relic of the Reaper, which created nice portals through a demiplane known as the Realm of the Reaper, as well as preventing you from dieing. As it turns out, it was created by Mephestopheles for the head of his preisthood on the Material. When you freed him, he used its magic to switch your places. He was free to roam the Material, and you were bound to Cania. The only way to get back to Toril was to learn the Reaper's True Name, and order him to send you back.

So, after poking around the town you first appeared in for a bit, you find out you need to seek out the ancient baatorian known as the Knower of Places, who resembled a pair of butterfly wings and a floating female head. So out you go, using assorted magics to guide you, until you arrive at her (strangely chaotic) home, after defeating a couple of Guardians Mephestopheles places to bar the path (the first two were killed previously). Her home resembled a large room, with raised platforms every so often. Seemingly at random, objects (like living trees and pieces of castle walls) would come flying past (and through) you. As it turns out, she can only answer one question regarding where things are, per person. Ever.

So, the PC asks for the location of the Knower of Names, and she gives a seemingly meaningless answer (it makes sense once you get there, though). So you head off through a portal, and after fighting your way past a Blood War battleground (still on Cania, mind you), and come to the place where the Knower of Names is buried, along with 11 fiends that used to be Mephistopheles's generals, when you're attacked by the fifth Gaurdian, who was the only loyal general Mephistopheles had lef following a rebellion.

So you unearth the Knower of Names (who resembled an icey white, human-sized celestail), and she explains what happened. Basically, she was Mephistopheles's lover. So, she finds out the names of those who would betray him. The names of most of his closest generals come up. So she goes and tells him. In an attemt to prove her wrong, he goes and creates a ficticous Baron of hell, and attempt to get his Generals to rebel against him. He succeeds, and, in a fit of anger, he imprisons the Knower of Names as well as all 11 traitorous generals beneath the ice, and appoints the only loyal one to stand as Guardian over them.

So, you ask her for the True Name of the Reaper, and she tells you in exchange for a couple of items you picked up alng the way. If you asks her for any other True Names (including those of mortals), she charges you anywhere between 1-3 hundred thousand gold each. She then teleports back to the town where you started, and you order the Reaper to send you back to Toril using his True Name. You then confront, and defeat Mephistopheles in combat, and when you wim, you get the option to either kill him, or show him a bit of mercy, and order him back to Cania (where he will undoubtably be plotting revenge and his return to Toril).