Pleisthenes
Pleisthenes was the ill-fated son of Atreus who had been brought up by Thyestes. After Atreus gained the crown of Mycenae and Thyestes was banished, Thyestes ordered Pleisthenes to kill Atreus. Apparently neither Pleisthenes nor Atreus knew their actual relationship, for Pleisthenes attempted the murder and Atreus killed him in self-defense.