Nizidramanii'yt

Nizidramanii'yt was a black dragon who allied with Jon Irenicus, attacking Suldanessellar and once there guarding the Goblet of Life to prevent anyone from following Irenicus to the Tree of Life.

History
Gorion's Ward and companions had to face Nizidramanii'yt and acquire the Goblet. They could fight or bargain for the Goblet, but the dragon would only give it for all of their treasure (gold and magic items), lying that he had no other treasure himself.

Gameplay
The protagonist of Baldur's Gate II: Shadows of Amn must face Nizidramanii'yt and acquire the Goblet near the end of the game.