Mordred

Birth
Mordred was born when King Arthur had accidentally slept with his sister, Morgawse.

May-day
When Merlin tells Arthur that a child born in May will be the cause of his destruction, he takes all children including Mordred, and puts them on a ship. He has the ship destroyed, however, miraculously, Mordred survives.

Childhood
A nice family finds him and raises him well until he turns 14, when he leaves to go to Arthur's court.

Orkney Boys
Mordred can be considered one of the Orkney boys as he is always around them and they are generally the knights he hangs out with. They are also all half sibilings, and share the same mother.

Exposing Lancelot and Guenever
Mordred helps Agravaine and the Orkney Boys try to expose Lancelot and Guenever, but when Lancelot ends up killing Gaheris, Gareth, and Aggravain when they try to ambush them. Mordred is the only one to survive.

Taking Over
Mordred takes over the throne when Gawain convinces Arthur to raid Lancelot's lands. He convinces the people that Arthur has died by forging letters and crowns himself King. When Arthur comes back, he sees this and they both fight each other to the death. Mordred dies right away after Arthur stabs him and Arthur dies later on.