They're playing cards. They're game aids. They're playing cards. They're game aids. ... They're playing cards and game aids.
From the campaign:
Character Cards are a tool for creating fantasy stories, whether you're writing a piece of fiction or running a roleplaying game.
Each card details an individual who can be readily slotted into your story. Or, if you want more variety, they're designed to be easily combined to create truly unique characters.