* He protects Harry: Snape, despite his outward gruffness and disdain for Harry, is secretly working to protect him from Voldemort. He provides vital information, including the location of the locket Horcrux, and even risks his own life to keep Harry safe.
* He joins the Order of the Phoenix: Snape's loyalty to Dumbledore and his dedication to defeating Voldemort lead him to join the Order, putting himself in danger alongside other members.
* He defends the students: Snape, as Headmaster, bravely faces off against Voldemort's forces during the Battle of Hogwarts, putting himself on the front lines to shield students from harm.
* He makes a sacrifice: Snape's ultimate sacrifice is the most powerful act of good in the book. He reveals his true loyalty to Dumbledore, his past relationship with Lily, and the depth of his regret for his mistakes. He dies protecting Harry, fulfilling Dumbledore's plan and ensuring the downfall of Voldemort.
It's important to note: Snape's actions aren't always easy to understand or appreciate. He is a complex character who is capable of both good and bad. His actions, driven by love and loyalty, are ultimately what help Harry achieve victory and bring about the downfall of Voldemort.