If your guild won Castle Siege Battle, you can use Senior Mix and get rewards.
You can find Senior Mix in Castle Room (179 214).
Reward 1: 1.500 W Coins (100%)
Reward 2: 3rd Wings, 4th Wings, Jewel of Kundun, Jewel of Kondar (random)
(! Note) Wings will come with random options and for random class.