* Lily's Sacrifice: The most important factor was his mother Lily's sacrifice. When Voldemort tried to kill Harry as a baby, Lily stepped in front of him, shielding Harry with her love. This act of self-sacrifice imbued Harry with an immense magical protection, making him the only known person to survive the Killing Curse.
* The Love Charm: The Killing Curse, while incredibly powerful, could not kill someone protected by love. This was the specific power of the charm that Lily's love unknowingly bestowed upon Harry.
* Voldemort's Overconfidence: Voldemort, arrogant and blind to the power of love, never considered this potential weakness. He assumed his magic, and his use of the Killing Curse, was invincible.
* A Bit of Voldemort's Magic: In the process of attempting to kill Harry, Voldemort unknowingly transferred a part of his own soul into Harry. This connection played a vital role in their lives, both as a weakness for Voldemort and a strength for Harry.
* The Power of Love: Throughout his life, Harry was surrounded by love: his parents, his friends, and even his enemies who were ultimately trying to protect him. This love helped him face the dark forces he encountered.
It is important to note that the story emphasizes the importance of love as a powerful force in the world. Harry's survival was not just due to luck or coincidence, but a testament to the strength of love and sacrifice.