Mordred was the illegitimate son of King Arthur Pendragon and his half-sister Morgause. Merlin prophesied that a son born on May Day would rise up and destroy both him and Camelot. To prevent this, Arthur had all the children born that day put on a boat with a leak and sent to sea. Mordred survived and eventually returned to his mother, where he was raised and educated to be a knight.
In Camelot, he became a rival and enemy to the first Black Knight Sir Percy of Scandia. Mordred would eventually lead an uprising against Arthur that would lead to both of their deaths. Shortly before he died, Mordred killed the Black Knight.
Mordred was later resurrected in the 20th Century and served the demonic Necromon, coming into conflict with the most recent Black Knight (Dane Whitman) and Captain Britain.Mordred, as he was garbed while serving the Nethergods
In his appearances in the Black Knight series in Hulk Comic, Mordred is often mistakenly referred to as Modred. However, he has no connection to Modred the Mystic.