flavor text

noun1

1. •
   Text printed on a card or within the rulebook of a tabletop game or a menu in a video game which does not affect the game's mechanics, but gives background information on characters, places, etc. to enhance the game's atmosphere.

   • In the old days of Magic the Gathering, the flavor text was almost all serious, sometimes even with quotes from Shakespeare or Edgar Allen Poe thrown in. — 2008