You can grant additional option/stat to your equipment by binding a Card to it.
You may also get higher grade Cards through Card Binding. To Bind Cards,
- Go to Inventory
- Tap Bind and select the Cards you wish to Bind
- Tap Bind
You can get a New Card by Binding 3 cards at maximum and randomly get a higher grade Card by Binding with the different grade Cards.
When you bind 3 cards with the same grade, you have a chance to get a Card of the next grade.