Celestiel is a collectible card game focused on a robust base card game fundamental, supplemented with giantess, growth, shrink, and monster girl related themes.

In Celestiel with the help of a character of your choice, you battle with other characters for the entertainment of Celes. You'll have the help of your character, followers, relics, and action spells to come up with a strategy to run the opposing character out of lilumi. You will use your character's vigor, combined with essences to fuel these cards. Characters generally excel at one thing or another, whether it is burning all you essence for a big boost in power, or shrinking the opposing followers so you can eat them, to growing your followers into giantess', outgrowing their clothing in the process, so they can stomp the opposing followers.