I’m not going to call them knights, because in the Dark Ages that concept—at least as we think of it—didn’t exist. There may have been a round table for all I know. They certainly could have made a round table if they wanted to. But these warriors did not wear plate armor from head to toe and they probably did not fight from horseback—certainly not with lances—because the stirrup had not reached Europe yet.
The ones that seem to have some basis in the older traditions are Bedivere (Bedwyr), Kay (Cei), Gawain (Gwalchmai), King Uriens and his son Owain, and Illtud. (I know, Illtud doesn’t show up in most of the versions of the Arthur legend, but he’s interesting, so I may include him.)
Bedwyr of the Perfect Sinew was a one-handed warrior. And, in Culhwch and Olwen, he wielded a magic lance. He and Cei were close friends. Being one-handed makes him interesting to work with.
Cei was not Arthur’s foster brother or the son of Ector in the older traditions. He was supposed to be exceptionally stubborn. He was also credited with several supernatural abilities—to be able to withstand fire or water better than anyone else, to go nine days without sleeping or breathing (?!), to grow as tall as the tallest tree, and to be able to radiate heat from his hands. A wound from Cei’s sword could not be healed. He was nevertheless killed and Arthur avenged his death.
Gawain was Arthur’s nephew, son of Arthur’s sister or half-sister Morgause and King Lot of Orkney and Lothian. Orkney and Lothian are both very far north. In some versions, though, his mother was Gwyar, who might have been one of Igraine’s sisters—making Gawain Arthur’s cousin rather than his nephew. Sometimes, Gawain has brothers listed as Agravain, Gaheris, Gareth, and Mordred. But these, other than Mordred, seem to be late additions.
Gawain also has a magic sword, given to him by the Lady of the Lake. His sword, Galatine, is nearly as potent a weapon as Excalibur.
Formidable, courteous, compassionate and loyal are the descriptors used of Gawain. He’s a mentor to young warriors and a defender of the poor and of women.
King Uriens of Rheged and his son Yvain (or Owain) are somewhat problematic for me. Rheged, which had been the western (and less Romanized) half of the territory of the Brigantes, would have been a very new kingdom. Since Arthur was not, could not have been, high king, it’s hard to picture the king of another tribal domain following him. Though, if Arthur was a war leader—not a king—he might have operated in Rheged at some point. And on way to look at Arthur is as the leader of a possibly small, but highly mobile strike force. That could be interesting.
Illtud (also known as St. Illtud) was Arthur’s cousin once removed. Igraine’s mother and Illtud’s were sisters. He was one of Arthur’s warriors and, later, followed a Welsh king until a religious . . . event. He then left his wife to become first a hermit and then a monk. He may have founded a monastery at Llanilltud Fawr (translated: Illtud’s Great Church), which became one of the great monastic schools in Wales. (The monastery was real, but it may have been older than Illtud.) His students supposedly include Saint Patrick, Saint David, Taliesin, and . . . Gildas. The very same Gildas who failed to even mention Arthur. Hmm. . . .