The story is based on crossover of videogame "For Honor", mostly about Black Prior character and MLP.
The knights of the order of Saint Balaur have long been known for their righteous deeds, piety, and impeccable observance of the code of honor. But when a monstrous cataclysm occurred, which led to the appearance of a legion of ruthless warriors who turned a once prosperous world into a crucible of war, the Black priors were born - heartless executioners for whom honor is an empty word.
The main character is a Black Prior named Gabriel who remains faithful to the original plan of the order. He followed the code, protecting the weak from the misery of disaster, sparing no effort. But the soldiers of The black Stone Legion who had opposed them had far more forces and supporters, including the Black priors who had succumbed to false persuasions under the leadership of Vortiger. So they went to the fratricidal war with black joy - and despite all the bravery and righteousness of their thoughts, the loyal priors were smashed to smithereens - Gabriel's fiancee dies on his hands, all the Chaplains and the high master are killed, and a priceless artifact is mercilessly destroyed by Vortiger - but this blasphomous act had consequences.
God's will or righteous anger saves Gabriel from death, sending him to the magical lands of the hitherto unknown world - Equestria. Having suddenly lost everything he loved and vowed to protect and found himself in a new unfamiliar place, the knight took it as a personal penance, a chance to atone for his sins and failures. But will he be able to cope with fate? Will he be able to forgive himself, or will he be condemned to repent for eternity? Or will he ever be given a chance to be forgiven? This is what Gabriel, the last of the Black Priors, will have to face.

Disclaimer:
I do not own "My Little Pony: Friendship is Magic" or "For Honor". They are the property of their respective owners, and are not my intellectual property.
There is no financial gain made from this nor will any be sought. This is for entertainment purposes only.