Originally called Archetype Saber, he is the version of Saber that was to be used in the original Fate/stay night novel that was penned and left uncompleted. He would later make an official debut in Fate/Prototype as a Saber from an entirely different time tree, complete with his own characterization and contextual differences compared to the Saber from Fate/stay night.
Arthur plays a role in Fate/Grand Order as well: he is chasing Beast VI across time and space, with the intent to slay it for good after unsuccessfully attempting such in 1991 and 1999 of his own time tree.
