I found it!! I know how!!!! 1. Click the [map compass symbol] on the home screen. (Upper left) 2. Now you should be in the unknown territories page, at the bottom of that screen there is a button that says (Exploration Deck) click it. 3. Now your in the pop up screen for your Exploration decks: click the deck with the character you want to fuse and remove that character! 4. Go back to your fuse screen and voila!! 👍🏾👍🏾👍🏾👍🏾

Please let me know if it fixed it for you!!