Level 400, Completed both previous quests, 30 Million Zen (at least).
Further upgrade your class.
May wear 3rd level wings
To complete this quest, speak to Priest Devin on Barracks of Baglass.
Hunt the respective monsters to collect 3 of each item. Dark Phoenix (Icarus) for the Feather, Death Beam Knight (Tarkan) for the Flame, and Hell Maine (Aida) for the Horn. Return for Priest Devin for the second stage of the quest.
Once the mission is done, go back to Devin and get the third and final stage of the quest.
Go deep inside the Barracks, and you will reach the Guardian, asking for permission from Devin. Once he lets you in, slay the foul beast and return to Priest Devin to complete your quest.