Taskmaster Fizzule

Taskmaster Fizzule is a level 30 elite mob located outside a tower just northwest of the Sludge Fen in the contested territory of the Northern Barrens.

Pre-Cataclysm
For reasons unknown, this Dark Iron dwarf was part of the Shattered Hand, a guild of rogues from Orgrimmar. Fizzule worked as a secret agent, infiltrated in the Venture Trading Company.

He was initially, and would only become to those that fired a  twice and then "saluted" him, which is only an option available to Horde rogues undertaking the quest chain which starts with Shenthul at the Cleft of Shadow.

He then gave upon completing, making approaching him easier.

Cataclysm
Taskmaster Fizzule is now present in the northern part of the now divided Barrens, Northern Barrens. However, since rogues no longer receive the quest or a flare gun, Fizzule is now always hostile. It's unknown if he is still with the Horde (in secret) or permanently part of the Venture Co.

Treason?
Fizzule's alingment with the Horde is now a mystery, in World of Warcraft: Cataclysm, Fizzule is stated to be hostile even for Horde players, which suggest he may have betrayed the Shattered Hand.

Or he may have been betrayed by the guild of rogues, which is reinforced before the Cataclysm, after completing the quest, Shenthul starts talking about how efficient Fizzule was and that being a field agent of the Shattered Hand is a dangerous work.

This suggests that Taskmaster Fizzule was of no use to the Shattered Hand after, and so, the guild tried to do something against the Dark Iron to get rid of him.

Fizzule's treachery to the Horde is further reinforced by the removal of all quests involving him from the game in Cataclysm.

Strategy
Taskmaster Fizzule has an impressive amount of health for a level 30 NPC and is capable of laying considerable damage in opponents of the same level, hence his elite status.

However, it's not advisable to fight or kill Fizzule, for he is a quest giver and drops no loot.