Bloodline curse linking him to the Ebony Blade and feeding its magic with his own inner darkness, allowing the sword to slice through anything, disrupt magic and enchantments, deflect energy or absorb and redirect it, manifest his armor mystically, increase his strength and stamina, expel raw force, and even resurrect him after death provided he was in contact with sword; can sense the sword at a distance, telekinetically retrieving it or teleporting into its presence
Accepted membership as a reservist in Avengers (1st series) #71. Did not serve as an active member of the roster until #255.
The legacy of the Black Knight begins with Sir Percy of Scandia during the age of Camelot. The nature of the Ebony Blade's curse was that the bloodline of Percy could continue to wield it throughout the centuries, including other Black Knights such as Sir Raston, Eobar Garrington, William, Henry, and finally Dane's uncle and predecessor, Nathan Garrett. Others have wielded the Ebony Blade in the modern era, such as Jacks Chopra, Augustine du Lac, and even the Black Panther. An unrelated female Black Knight served with the Young Masters. The Black Knight(s) is also a position in the Hellfire Club or Trading Company, currently held by the Fenris Twins.
Black Knight has occasionally tried to leave the Ebony Blade behind. He wielded a photonic blade, or "Sunsword", beginning with Avengers (1st series) #343. Later, he was named the new Pendragon of the modern age by the Lady of the Lake in Heroes for Hire (1st series) #2, with new enchanted weapons and armor. After some time apart, though, he was fully reclaimed by the Ebony Blade and its curse in Captain Britain and MI-13 #10.