Drisnak of the Red Eye was a Goblin chieftain of Moria who lived in the Fifth Level near the Hall of the First Fathers. He dressed himself in rugged Elvish clothes (or perhaps Dunadan clothes) and had an obsession with secretive lore.
Sauron's trusted agent in Moria, Drisnak was aware to some extent of his master's Ruling Ring, but was not certain whether to find it for himself or hand it over and be rewarded for his allegiance to Sauron. Nonetheless, he sent scouts to report on all movements in Eriador and also arranged an alliance with Saruman, who presented himself as the Dark Lord's outright servant alone.
Drisnak was the chieftain of the Servants of the Flame and dominant amongst the Gongs of Moria. His increasing influence, connection to Saruman and favour with Sauron made him a bitter rival for the likes of Black Uruk viceroy Grishlug and Great Orc lord Mazog, both adversaries to the throne of Moria. Though a lesser goblin, he feared none but the Dark Lord and the Nameless Terror themselves, the latter of which he dreaded more than the former due to closeness.
The incoming arrival of the Fellowship of the Ring reached his sharp ears and so Drisnak persuaded a pack of wild Wolves and Wargs to attack the group on the road to the mountains, promising them fresh meat as a treat. Cunning as always, he did not follow Grishlug and the others to the Chamber of Mazarbul, but instead remained hidden and practiced a ritual to awaken the "Fire-demon" and trap the intruders. Raised from its slumber, the Nameless Terror charged through the ancient corridors after the Fellowship.
With Grishlug dead and Sauron's support (given his apparent loyalty), Drisnak confronted Mazog for the throne of Moria before the eyes of their hai. Though an able warrior, the Servant of the Flame was outmatched by the latter's superior force and was slain. His carcass was left for Mazog's wolves to feast upon, striking fear into the hearts of any goblins with rebellious plots in mind.
- Interplay´s the Lord of the Rings volume I