From NWN2Wiki

Devils, also known as "Baatezu," are outsiders native to the lawful evil-aligned plane of Baator. Unlike demons, devils maintain a strict and brutal hierarchy, with Archdevils at the top each ruling over one of the Nine Hells. They are locked in the eternal Blood War with the demons.

[edit] Traits

Most devils possess the following traits:

• Immunity to fire and poison.
• Resistance to acid 10 and cold 10.
• Darkvision: All baatezu can see perfectly in darkness of any kind, even that created by a deeper darkness spell.
• Summon Baatezu (Sp): Baatezu share the ability to summon others of their kind (the success chance and type of baatezu summoned are noted in each monster description).

[edit] Devils in NWN2

Neverwinter Nights 2 features the following devils:

• Erinyes
• Horned devil (or "cornugon")
• Imp
• Pit fiend

One devil in particular plays a minor role in the NWN2 main storyline, Mephasm, first met as a servant of the warlock Ammon Jerro.