The existing reward card airdrop from Thran ends and a new card comes out as a reward.
These cards cannot be sold, but can be used in the game. It seems to be a policy to maintain the price of the card, but so far it has been successful. Thanks to this, the price of the existing reward card is rising.
Common seems to rise and then come back to normal, but rare continues to rise. Previously, the floor price was around $0.002, but now it is around $0.003. There seems to be a lot of potential for further increases in the future.