Costume Chamber is a new type of Summon featuring only Costumes. Costumes can be summoned using Costume Keys or Gems.
Costume Keys can be acquired from Costume Quests. Every month offers two Featured Legendary Costumes that have an increased chance of being summoned.
Costume Chamber opens at 07:00 UTC on the 3rd Monday of each month and is open for 48 hours
During those 48 hours, a new Costume Quest can be found from the Quests Map
You need to have the original Hero before a Costume can be used