The Undead Chest is a limited edition Chance Chest that was released on September 12th, 2014 and ended on September 15th, 2014. The new Epic released in the chest is the Undead Robes which is a Spirit/Earth Armor
It was rereleased in October 2, 2014, and will be available until October 6, 2014.
1 Chest: 35 Gems
11 Chests: 350 Gems
40 Chests: 1,200 Gems
11 Chests: 5 Spirit Fusion Boost Armors