Seth, the god of disorder, murdered his brother Osiris, the god of order. Seth was furious because his wife,
Why did they kill Osiris?
Some versions of the myth provide Set's motive for killing Osiris. According to a spell in the Pyramid Texts, Set is taking revenge for a kick Osiris gave him, whereas in a Late Period text, Set's grievance is that Osiris had sex with Nephthys, who is Set's consort and the fourth child of Geb and Nut.
How was Osiris killed by Seth?
According to the form of the myth reported by the Greek author Plutarch, Osiris was slain or drowned by Seth, who tore the corpse into 14 pieces and flung them over Egypt. ... His son Horus successfully fought against Seth, avenging Osiris and becoming the new king of Egypt.