What are Costume Keys, and how do I get them? Katherine December 07, 2019 00:25 Updated Follow Costume Keys can be acquired from Costume Quests. Every month offers two Featured Legendary Costumes that have an increased chance of being summoned. Five Costume Keys are needed for a single Summon. Related articles What is the Costume Chamber? Reminder Regarding Hero Costumes & Defence Teams What are Costume Quests? What are the Hero Costumes? High-level ascension materials and where to find them Comments 0 comments Article is closed for comments.