The superhero from the comic Elemenstforce, which is set in Alternate Battal. Cardman also makes a few appearances in the animated ElamenSTAR Shuffle (the first appearance being in the episode Furniture defenses). No other characters from Elemenstforce appear in the animation.
Cardman's powers are derived from playing cards based on the Elemenstor Battles CCG, which exists within the Alternate Battal world.
Cardman was the leader of the Elemenstforce team until he was killed by the Dark Jesterfield.