Legendary Wildcards will help you to focus your efforts on upgrading the Legendary cards that you want. After collecting Wildcards, you’ll be able to exchange your Legendary Wildcards for Legendary Cards on the Wildcard Shop that you have already unlocked, with a rate of 1 Legendary Wildcard per Legendary Card. 

You can find your Legendary Wildcard in the Inventory by tapping on the backpack icon in the Map view.

The Wildcard Shop will be periodically available in Our World, approximately once per month.

During Group Boards season, you will be able to find Legendary Wildcards as Season End Rewards from Gold I+ (Tier 11+) onwards. You can also find Legendary Wildcards from Bait reward level 8 onwards, as well as from Special Events. In the future, you will find them in multiple other places too.