(Child generation, age difference) (The heroine Harry is in the same grade, but the actual age difference between him and Snape is only 2 years) Original heroine vs. Snape (try not to occ, occ is my fault) The pharmacy genius in the junior class who has just received the notice of admission to the master's and Ph. D. Program appears in the wizarding world the next day, secretly spying on the plot progress of the protagonist group with the help of important plots that he only remembers. Carrying his mother's last wish, he originally planned to secretly make up for his wounds and gain experience, but because of the Mirror of Erised, he found this sudden direction in his life - to save everyone who died in the war. In the summer of 1991, Trelawney's sudden prophecy made Dumbledore know about the "Guardians", so Snape was arranged to observe and protect Usa Black. I originally thought he was just the same "poor guy" as he was when I was young, but I didn't expect him to be a rich and capable liar. (The author doesn't have enough IQ and brainpower.)
Mission: Redemption, Opposition to Campus Isolation, Protection