Spark is an egotistical unicorn who has no idea what he's doing, but doesn't like to lose.
Phantom is a powerful red unicorn with an intense love for his friends and a short fuse.
Crimson is an ex-alicorn who lost his kingdom to his own rage.
Brimstone is a gray pony who is a child of Sombra and also somehow a pegasus.
Maple is a war scarred cyborg.
Shifter is a changeling that doesn't like to get booped on the nose.

The six of these friends/rivals/lovers? are sent to Tartarus by Princess Luna on a quest to ask her step brother, Prince Dusk, for a cup of sugar as well as a few golems made from moon rock. Instead, they are greeted by an army of demons.

Good luck with that.

((This is based off personas in a chatroom I hang out in. Completely written for fun, in no way serious or to be taken seriously))