If you collect one card for each space then you are able to trade it in for a permanent exclusive item. Each card has it's own rarity. S being the rarest, S4 and fumbi the second rarest, and the rest being the same chance of obtaining. You may obtain these cards from 2 methods: Inside 900 and 1500 PEN Capsules which can be obtained through Cash Points upon opening these you will get 1 out of the 10 cards. PEN capsules have a higher chance of giving rare (S4, S and Fumbi) cards. However, it is unknown just how much more likely those cards are to come. You can also use the free method and finish a 6-player, 4-minute+ battle.