Re: [DMM] Puzzle of Walkure
I honestly dont know what that error means but basically you can only combine up to ++. You will need 4 basic cards with no pluses (shown by tiny circles under the cards rarity) of the same character and they have to be the same rarity(N, bronze, silver, or gold). You can combine cards with same amount of pluses, so you can combine a card with no circles with a card with no circles and a card with one circle with a card with one circle. Combining 2 "+" cards makes a "++" which is the highest a card can go.