He's the son of Geb, god of the earth, and Nut, goddess of the sky. He's also the brother of Isis and Osiris.
Consorts & Children:
He's the brother-husband of Nephthys, and possible father of Anubis.
Other names for him include Set and Sutekh, and he's often portrayed as evil.
Notable Stories Involving Him:
The most well known story involving him tells how he killed his brother Osiris by tricking him into a box that had been fitted to Osiris's measurements, then dismembered him and scattered the pieces. His nephew Horus later avenged Osiris's murder after a series of conflicts.
Seth Around the World:
His Greek equivalent would probably be Eris, though he also has a counterpart in the Norse Loki and, to an extent, the Greek Hermes.
SOURCES: Wikipedia and Encyclopedia Mythica