Severus Snape's character arc in the Harry Potter series is one of the most intriguing. Initially portrayed as an unsympathetic Potions master at Hogwarts, particularly towards Harry, Snape's tough exterior belies a troubled past and a deep sense of remorse over losing the love of his life. His morally ambiguous nature and complex development make him an anti-hero with a strong appeal. Snape possesses intelligence, adaptability, and an unwavering loyalty to the good cause, as exemplified by his allegiance to Dumbledore until the very end.
Snape's Everlasting Love For Lily
In "The Prince's Tale" chapter of Harry Potter and the Deathly Hallows, readers gain a deeper understanding of Severus Snape's character. After Voldemort orders Nagini to kill Snape, mistakenly believing him to be the master of the Elder Wand, Snape passes on a mysterious substance to Harry before passing away. Harry later views Snape's memories in the Pensieve, witnessing Snape's childhood memories, his connection to Lily, and their eventual falling out.
Snape's infatuation with Dark Magic had already caused a strain in their friendship, but it was calling Lily a "Mudblood" that led to its ultimate demise. Although Snape apologized, Lily condemned him for being a Death Eater, a claim he refused to refute. Harry later witnessed Snape's immense regret for revealing Sybill Trelawney's prophecy to the Dark Lord and saw him plead with Dumbledore to hide the Potters in exchange for "Anything." After Lily's death, Snape was heartbroken, and Dumbledore informed him that her son, Harry, had survived the attack. Despite his desire to die, Dumbledore discussed the way forward, knowing that the Dark Lord would return. He enlisted Snape's help in protecting Lily and James Potter's son.
Snape Creates His Patronus
Through the ever-changing scenes, Harry discovered more about Snape's past. He left the Death Eaters because of his love for Lily and learned the truth about Dumbledore's death. Most importantly, he discovered that Voldemort had unintentionally created a seventh Horcrux when he used the Killing Curse on Harry during the attack on Godric's Hollow. A fragment of Voldemort's soul attached itself to Harry when Lily sacrificed herself to save him. "As long as that piece of soul, which Voldemort has inadvertently left inside him, remains attached to and protected by Harry, Voldemort cannot die," explained Dumbledore in Harry Potter and the Deathly Hallows. This meant that Harry's death was necessary to defeat Voldemort. Snape understood that Dumbledore's end goal was to take down Voldemort at any cost. When Dumbledore revealed that Harry must die at the hands of Voldemort, Snape was horrified and accused him of using Lily's son "like a pig for slaughter."
Dumbledore was moved by Snape's actions and asked if he had developed feelings for Harry. In response, Snape conjured a silver doe from his wand with the incantation "Expecto Patronum!" The doe flew out of the window, leaving Dumbledore to turn to Snape and confirm what he already suspected. "Lily! After all this time?" he asked. Snape's reply was simply "Always." The fact that Snape's Patronus was the same as Lily's, a doe, symbolized his undying love and loyalty to her. Despite their tumultuous history, Snape never stopped loving Lily and she remained his guiding light. His protection of Harry was a testament to this love.