Why did Snape kill this character in Half-Blood Prince?
I was watching Harry Potter and the Half-Blood Prince but I didn't get why did Snape Kill Dumbledore?
This answer is one giant spoiler, and most spoilers are there in the open. Sorry, there's no way to do it without them.
Dumbledore's Death was pre-arranged by Dumbledore and Snape back in The Half-Blood Prince (starts at 0:54):
Snape had to kill Dumbledore. Firstly, because it was an act of mercy for Dumbledore, as he was already dying, first from the curse he received when he put on the Gaunt ring, and second when he drank the potion from the cave with the locket horcrux. That's what Dumbledore means when he says "Severus. Please.".
Snape also had to kill Dumbledore to remain a trusted Death Eater, and Voldemort's right hand. He needed to be a double agent in Voldemort's ranks in order to be able to help Harry & Co on their quest, such as when he sent his doe Patronus to the lake where he hid the sword of Godric Gryffindor.
As to how Snape became a double agent - it was after Voldemort had become determined to kill Harry as an infant, thus endangering his mother, Lily, whom Snape love since they were children.
Snape begged Dumbledore to protect Lily (see the video below); however, Lily still died. Snape continued to serve Dumbledore as a double agent to honour her memory (shameless plug), which was living in her son (and thus "You have your mother's eyes.")
Pictures about "Why did Snape kill this character in Half-Blood Prince?"
Why did Snape kill Severus?Dumbledore, aware that Voldemort had ordered Draco to kill him, had asked Snape to kill him instead as a way of sparing the boy's soul and of preventing his own otherwise slow, painful death.
How did Snape feel about killing Dumbledore?Once he arrived, Draco lowered his wand. Dumbledore pleaded with him. Snape hesitated, then cast the Killing Curse, killing Dumbledore. After he killed Dumbledore, Snape ordered the Death Eaters out of the school and took Draco with him.
Did Snape kill Dumbledore for Draco?Having been told half of the prophecy by Severus Snape, Voldemort came to believe his mortal enemy to be Harry Potter. He travelled to the Potters' home in Godric's Hollow and murdered James and Lily Potter, whom died protecting infant Harry.
Why Snape's Avada Kedavra Was BLUE When He Killed Dumbledore - Harry Potter Theory
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