Snape was once the death eater, but when his superego was provoked, he chose to breach from Lord Voldemort and join in the team of Dumbledore without hesitation. The ultimate dedication of Snape to the bright world was to accomplish the plan which Dumbledore proposed to kill Voldemoret. The essence of this plan was to protect Harry Potter by sacrificing Dumbledore and Snape.Complying with the plan of Dumbledore, in Gryffindor tower, Snape used Avada Kedavra spell to end the life of Dumbledore, who have been poisoned and about to die. Snape created a false scene to make Voldemort believe Elder Wand was actually controlled by him. He bravely faced the impending death. On May 2nd 1998, half-blood prince Severus Snape was skilled by Voldemort. He was bitten by snake Nagini and died. His short but extraordinary life was ended at 39 years old.