Abaddon the Redeemer, honored member of the Mournival, First Company Captain of The Lunar Templars, 16th Legion of the Legiones Astartes and the entirety of the Justaerin, except Garvial Loken, perished upon the Ork attack planet, DESTROYAH!!! during the Ullanor Crusade.
Posthumously renamed Abaddon the Hero by the Emperor, he and his brothers died honorably to ensure mankind would walk the Golden Path.
But what if this was not so, what if the Redeemer and his brothers did not die that day, and instead were, by the Orks Waaagh energy and collapsing Mork Portals, teleported to a planet hidden by strange magic from the empires of the galaxy.
A planet home to a kingdom of Equestria.