There is card exchange event in KRO
http://ro.gnjoy.com/...?Seq=438&kind=A
1. Player can turn in their card to 1 card coin (MVP card can be turned in for 100 card coins)
2. and then turn in 5 card coins back to receive 1 random card, it can be rare card or even MVP card.
This event last for 1 week in the first week of each quarter.
*When turning in card. There is a chance to gain jackpot that receive 5 card coins instead.*
KRO just improve this system by player can exchange multiple same card at once (If jackpot triggers. All card will gain jackpot bonus)
Also player can turn in all card coin they have at once. (continuous process)
Edited by Sigma1, 05 July 2020 - 09:28 PM.