There was once a earth pony, named steel rain.

He hunted demons, and other foul creatures during Grogars time, and had even fought the foul Ram.

Sealed away by the Demons, and Grogar himself, out of desperation, using vast amounts of dark magic to seal him away.

Too bad gusty got to Grogar, and sealed him away too.

The demons were also sealed deep within tartarus, along with several fiends, when they banished Steel Rain from this plane as a final act.

Many millennia later, 5000 years, approximately, one Twilight Sparkle does the impossible, and manages to connect to the realm, after becoming the Element of magic.

What he does not realize, is a lot of things have changed during the life of pony kind, and they lost some knowledge of their old magics.

Quite annoying, he would say, since he is a Grandmaster Geomancer.

He may as well teach her whatever he knows, and show her the magic scrolls he had, right up and even beyond his banishment and sealing unto this realm.

Besides, he could use the experience in teaching.