In the [Inventory] on the bottom left of the game,

You can check all heroes, monster cards, and equipment you own.

Growth and Enhance of the hereos are also avaialble here.

■ Inventory

 1. Hero: Manage heroes such as checking Hero information, growth, sale and Fusion.

 2. Monster card: Check the information about the Monster cards you own.

 3. Equipment: Enhance, Sell, Check the information about equipments you own.

 4. Accessories: Sell, Check the information about the accessories you own.

 5. Materials: Check the information of various materials you own. You can also craft set items here.

 6. Dimensional Boss card: Check the information about the Dimensional Bosses you own.

7. Treasure Chest: Using the adventurer's Mark, you can acquire Gems, Heroes, Monster Carda, and Gold.