Neverwinter Nights: Hordes of the Underdark

Neverwinter Nights: Hordes of the Underdark is an expansion pack for Neverwinter Nights produced by BioWare and published by Infogrames Entertainment (now Atari). The followup to the Shadows of Undrentide expansion, Hordes of the Underdark introduces a new campaign, six new prestige classes: Champion of Torm, Dwarven Defender, Pale Master, Red Dragon Disciple, Shifter, and Weapon Master; and other new features such as the ability to hire two henchman at once and the increase of the maximum attainable character level from 20 to 40. The Windows version also includes new scripting options for the Aurora toolkit.

Chapter one
The campaign is a followup to Shadows of Undrentide, featuring the same protagonist from that campaign.

Having escaped from the plane of shadows, the hero is currently staying in Waterdeep. While trapped within the plane of shadows, he/she encountered a mysterious artifact which would always return to him/her when thrown away. This magical artifact provides transportation to another realm watched over by a figure known only as the Reaper; the artifact therefore became known as the "Relic of the Reaper". Upon being mortally wounded, the bearer of the relic is teleported to this realm to prevent him/her from truly dying.

The conflict begins when drow and their duergar allies begin using Undermountain, a vast underground dungeon beneath Waterdeep that is the domain of the mad and ageless wizard Halaster before the city was even founded, as a means of reaching Waterdeep from their home in the Underdark and attacking the city from within. As Halaster had always been opposed to the drow, it is believed that something may have happened to him, and Durnan, an ex-adventurer who runs the Yawning Portal inn, which is built on top of an entrance to Undermountain, issues a call for adventurers to help him investigate, to which the hero responds.

In exploring Undermountain, the hero encounters a drow follower of the good goddess Eilistraee named Nathyrra, who leads him/her to where the drow have imprisoned Halaster. The hero defeats the drow guarding him and frees him, and afterwards learns from him that the invasion of Waterdeep is lead by a certain drow valsharess, or queen, who desires to rule both the Underdark and the surface world.

Desiring her dead, Halaster orders the hero to venture into the Underdark and kill her, and to prevent him/her from disobeying him, places a magical geas on him/her which compells him/her to obey. Nathyrra accompanies the hero and leads him/her to her Lith My'athar, a drow city in which the followers of Eilistraee have taken refuge from the Valsharess after their home city was destroyed by her forces.

Chapter two
Upon arriving in Lith My'athar, the hero is introduced to the Seer, the leader of the drow followers of Eilistraee. In discussing matters with the Seer, the hero learns that the Valsharess has managed to forge a pact with Mephistopheles, one of the nine Dukes of Hell, which forces him to do her bidding. The Seer also informs the hero that the Valsharess has made alliances with other races of the Underdark, including the beholders and the illithids, as well as a cult of necromancers who are providing her with undead. The Seer requests that the hero investigate the valsharess' transactions and find a way to keep her from supplying her army with these creatures. Eventually the hero is summoned back to Lith My'athar; once it is learned that the Valsharess' army is marching on it, and asked to lead the city's defense. In the resulting conflict the Valsharess is driven away and the Seer's forces pursue her to her lair intending to confront her there. Upon arrival at the gates to her fortress, the Valsharess commands Mephistopheles to bring the hero to her throne room, and after he does so, traps him/her within a magical cage and requests that Mephistopheles kill him. To her surprise, Mephistopheles defies her command and instead kills her retainers and afterwards releases the hero from the magical cage, allowing him/her to kill the Valsharess. After the Valsharess' death, Mephistopheles informs the hero that by commanding him to kill him/her, the Valsharess shattered their pact. This, he says, is because their fates were intertwined by the Relic of the Reaper, which was planted on the hero by Mephistopheles and caused the hero to aid him without his/her knowledge. Mephistopheles is now free to dominate the world of Toril and, to prevent the hero from stopping him, kills him/her and declares him/her banished to his own domain of Cania, the Eighth Hell.

Chapter three
Upon returning to consciousness within the Realm of the Reaper, the hero learns from the Reaper that the Reaper had been in the service of Mephistopheles all along. Though the Reaper expresses a disdain for Mephistopheles, it is forced to obey him because Mephistopheles knows the reaper's true name, the name given to one by the gods which defines the very essence of their existence. If a person were to know the true name of another, that person would be forced to do the bidding of the one who knows their name. The Reaper has been commanded by Mephistopheles not to allow the hero to return to Toril, but the Reaper informs him/her that if he/she were to learn its true name, Mephistopheles' hold on it would be broken and it could return him/her to Toril. The hero emerges from the Realm of the Reaper into the City of Lost Souls, where it is seen that Mephistopheles is devouring the souls of those banished to Cania and using them to reanimate the corpses of those killed in the battle between the forces of the Seer and those of the Valsharess, creating an army of undead which he intends to use to conquer the surface world of Toril and transform it into a new hell, one which he will be able to rule independent of Asmodeus. In exploring Cania, the hero learns of a being known as the Knower of Names, a member of a race who inhabited Cania before the devils claimed it as a hell who is said to know true names. She was once the lover of Mephistopheles, but was later banished by him to an icy prison. Eventually the hero locates this prison and frees the Knower of Names, who then tells the Reaper's true name to him/her. Upon returning to the Reaper, the hero calls it by its true name, ending Mephistopheles' domain over it and allowing it to return the hero to Toril. Upon returning to Toril, Mephistopheles has already reached Waterdeep, having traversed through the Underdark into Undermountain and then into Waterdeep itself. The hero confronts Mephistopheles, and in the duel that follows, Mephistopheles is defeated, ending his invasion and saving Toril from destruction. The knowledge of other true names, for instance that of the hero's henchmen or Mephistopheles provide additional options in the final fight and different endings.

Reception
Hordes of the Underdark received generally positive reviews. "Andrew Park", a user on GameSpot, referred to it as "a solid expansion pack that adds a substantial single player campaign and interesting new options for multiplayer enthusiasts".