The Black Knight, an ancient myth with many rumors surrounding it. Some claim he was trained by Nightmare Moon herself as her most powerful servant, others say he is human super soldier created to slay Princess Celestia, some even speak of him as a personification of death. Nevertheless, many ponies have reported sightings of this being throughout history, most of which never amounted to anything.

However, only several months after the return of Nightmare Moon, the fabled knight shows up at the doorsteps of Canterlot Castle for reasons unknown.

And the ponies of Equestria soon discover that the myths associated with him could not be any more wrong...

Part of the Shimmerverse

Recommend reading A Different Sunset first for better understanding