Let me clarify that this story started out over a year ago on FanFiction.net as just a Sonic and the Black Knight story, nine months before I became a MLP:FIM fan, but from chapter six on wards is when it became a crossover. This explains why the MLP characters aren't seen or mentioned in the first five chapters, but are seen regularly from chapter six on wards.
(This Message will be added to the beginning of chapter one so then none of you will have an excuse for not knowing why the characters don't appear)

A what if story to if Sonic stayed in the world of king Arthur. Over the years, King Sonic and the Knights of the Round Table have been ridding the world of every last Knight of the underworld that was left, but lately more Knights of the underworld have been appearing, and Sonic and The Knights of The Round Table are determined to put an end to their evil.