World of Warcraft Quests involving Trull Failbane:
Winterspring Alliance & Horde
Are We There, Yeti? - (Step 3) Take Umi's Mechanical Yeti and scare her friends with it:
Legacki in Everlook (Winterspring)
Sprinkle in Gadgetzan (Tanaris)
Quixxil in Marshal's Refuge (Un'Goro Crater)
When you are done, bring the Mechanical Yeti back to Umi.
Stratholme Alliance & Horde
Dead Man's Plea Go into Stratholme and rescue Ysida Harmon from Baron Rivendare.
The Stones That Bind Us - (Step 3) Free nine Servants of Razelikh, three Servants of Sevine, three Servants of Allistarj, and three Servants of Grol. Return to the Fallen Hero when your task is complete. You must remain within close proximity of the stones or the process will fail.
Feralas Horde Quest
The Strength of Corruption Talo Thornhoof at Camp Mojache in Feralas wants you to kill 12 Angerclaw Grizzlies and 12 Felpaw Ravagers in Felwood.
Felwood Alliance & Horde
Verifying the Corruption Seek out and destroy 2 Entropic Beasts and 2 Entropic Horrors while exploring Shatter Scar Vale. After checking to see if the craters there are still filled with corrupt fel water, return to Taronn Redfeather in Felwood.
Wild Guardians - (Step 1) Trull Failbane in Felwood wants you to kill 15 Raging Owlbeasts and 15 Ragged Owlbeasts.