The Tower of Althalaxx officially the most bs quest in the game.

This quest is super bugged in darkshire, once you get up top the npc's are surrounding the guy you need to kill and once you actually get up top to the tower if you come close to killing the casters they teleport downward and into the mobs that have about a minute spawn rate and then they come kill you, its green for me and its almost impossible to do.

Then skip it.

A lot of quests are bugged on Deathwing, so if you notice something is not right, you're better off skipping the quest. With the x7 XP-rate, you'll have no problems skipping any quest you don't feel like doing.