Arthur, Lancelot & Mordred
As Red states on her video on The Arthurian Mythos, Arthur, Lancelot & Mordred as changed depending on which version you're following. If Lancelot is the main character, Arthur will be portrayed as much more of a tyrant and abusive. If Arthur is the main character, Lancelot will be more egotistical and self-absored. And Mordred may or may not, be the son of Arthur, or even in leagues with Le Fey.
Depending on the Writer