First Appearance: Fantastic Four Annual #25 (1992).
Appearances: Fantastic Four Annual #25, Avengers Annual #21-22.
Years Active: Not applicable (see below).
The nephew of the Arthurian Black Knight, Sir Raston was defeated in combat by Kang the Conqueror and made to join his Anachronauts, a group of warriors who traveled through time, serving Kang. Sir Raston wields the Ebony Blade, but is not the Black Knight. (I'm told that during his first appearance in the "Citizen Kang" storyline he referred to himself as the "Black Knight of the 7th century," but I do not have confirmation of this.)
Notes: I'm told that the Anachronauts were heroes despite their association with Kang; one piece of evidence is their appearance in Avengers Annual #22 in which they stop some rogue Time Variance Authority robots from stealing the comet from which the Black Knight's Ebony Blade is made.