User blog comment:KrystalLBX/Guardians Fanmade Cards/@comment-26528086-20160820170147/@comment-24612605-20160820171820

Yeah  earth/water/fire/air are commonly an elemental quartet in various video games and TV shows. (Avatar anybody?)

I was thinking of making a seventh card based on a comedy relief character named Blunk. But he doesnt feel like he would be worthy of being a card.