Unlike other rarities, Mythic cards are crafted from fragments. Once you have 250 fragments follow these steps to add the card to your deck:
- Go to the Deck island from the main menu.
- Select the Mythic tab adjacent to your Inventory.
- Select the Mythic card from the list, and pay 5,000 Nixon coins to craft it.
- Go back to you Inventory and tap the filter button, choose to filter by Mythic rarity.
- Your new Mythic card should show in your Inventory now. Note: If you do not see your Mythic card you may have auto deck turned on. Be sure to turn this feature off when you are manually choosing cards.
For more information, check out the Mythic article.