The upgrade menu is used to combine cards. This will upgrade them and make them more powerful.
- Select a card to be the "base" card. This is the card whose stats will improve. (This is the card you will put in the middle Yellow Box)
- Select up to 50 cards or you can choose Transmetal to be materials. (These will be placed in the outlying boxes)
- Upgrading also requires Credits in addition to the cards.
Upgrading consumes all the materials. Only the base card will remain. The process cannot be reversed, so choose your cards with care. Material cards with higher overall ratings and rarity will give greater XP bonuses to base cards.
The following appears to be true separately for characters and weapons.
- The XP required to get from a specific level to another specific level (e.g. level 1 → level 2) is identical between cards.
- The amount of XP required increases as the level increases.
- The credit cost of using a card as upgrade material is linearly related to the amount of XP given by the material card.
- The linear relation between XP and credit cost is identical across cards.