Maugrim Korothir is an antagonist in the original campaign. He also has a role in the Hordes of the Underdark campaign.
Original campaign[]
Maugrim is a human who lusts for power to the point of madness. He serves Morag, orchestrating her schemes while she is confined to the Source Stone. His followers are the cult known as "The People of the Eye" (the "eye" being Morag's). It was under Maugrim's direction that Desther commandeered Helm's Hold and brought the Wailing Death to the city of Neverwinter.
He is first encountered in Chapter 2 at the pinnacle of the tower of the Arcane Brotherhood, an organization he seized control of. There he presents Lady Aribeth de Tylmarande to an apparition of Morag before being interrupted by the player. Maugrim and Aribeth relocate and are not encountered again until chapter 4.
In chapter 4, Maugrim must be fought to save Neverwinter from invasion. (He is a level 20 wizard and 8 cleric.) After his defeat, the city is safe from his army, but his mistress (Morag) must still be dealt with before she finds another pawn to further her schemes.
Hordes campagin[]
In the Hordes of the Underdark campaign, Maugrim makes an appearance for a single fight, alongside Grimgnaw. (His classes have changed to level 19 cleric and 2 fighter.)