Modred originally came from Camolot. King Arthur stories tell that his brothers are Agravain, Gaharith, Gaharis and Gwoen. Arthur is Modred's father. Modred killed Arthur in cold blood. Modred hated his father because Arthur left him with a witch.The witch's name was Mogona La Fae. She is Arthur's sister (Weird right).
Of course, considering that Mordred is a product of the Arthurian legends, there are many versions of his origins, exploits and intentions. There is one consistency though, in that Mordred is a symbol of chaos. Whether this be simply killing Arthur, or his using of Camelots laws to topple what they were set to uphold.
Mordred is the product of a brief love affair between a young King Arthur and Lady Morgase. Morgase who was betrothed to King Lot of the Orkney Isles, was sent with her parents to Camelot as a diplomatic emissary as a part of negotiations between the two kingdoms. While in Camelot the two met and fell into a brief love affair and unbeknownst to them, Morgase became pregnant. Morgase returned to Orkney after the negotiations were finished and married King Lot. Lot knew that Mordred was not his own, but for the sake of appearances kept this fact a secret. Mordred's upbringing was an unhappy one and from the hatred and mistreatment of his assumed father, the monster was born. Later in life, for one reason or another, Morgase saw fit to tell Mordred of his true father and he then set off to Camelot under the guise of being reunited with his birth father.