Help! My girlfriend is an ancient demon and if I don't please them, everyone will perish!

Chari is just another regular student at Saint Agatha's Catholic all-girls high school:

Abysmal grades,
Crippling social anxiety,
A demonic girlthing-friend that is going to end the world in three days,
And another girlfriend that has to stop her--even it means ending Chari's life...

[Edited from itch.io]