Lupin's Resignation

Remus Lupin's resignation as Defense Against the Dark Arts professor at Hogwarts, announced the morning after the climactic confrontation in the Shrieking Shack, brought a premature and sorrowful end to what many students considered the most effective teaching of the subject they had ever experienced. The resignation was not a voluntary departure for a better opportunity but a forced retreat, precipitated by Severus Snape's deliberate revelation of Lupin's werewolf condition to the entire Slytherin house at breakfast. This act of vengeance, following Snape's profound disappointment at losing the Order of Merlin, Second Class, and his fury over Sirius Black's escape, exposed Lupin's secret to the school community, making his continued employment untenable. Lupin himself acknowledged the inevitable backlash, predicting that by the next day, owls from parents would arrive demanding his removal, as they would not want a werewolf teaching their children. He accepted the resignation as the only responsible course, stating that after the previous night's events, when he had transformed into a werewolf on the grounds, he could not risk such a thing happening again.

The Revelation and Its Aftermath

The chain of events leading to Lupin's resignation began with his failure to take the Wolfsbane Potion on the night of the full moon. This potion, which Snape had been brewing for him throughout the year, allowed Lupin to retain his human mind during his transformation, rendering him a harmless wolf. Without it, he became a fully fledged monster. During the escape from the Shrieking Shack, the moonlight triggered his transformation, and he attacked the group, forcing Sirius Black to intervene in his dog form. In the chaos, Peter Pettigrew escaped. The next morning, Snape, seething with a personal grudge that dated back to their school days, told all the Slytherins that Lupin was a werewolf. The news spread rapidly. Hagrid, who had been celebrating Buckbeak's apparent escape, relayed the information to Harry, Ron, and Hermione, adding that Lupin was already packing. Lupin confirmed to Harry that he had resigned first thing that morning, explaining that while Dumbledore had managed to convince Cornelius Fudge that Lupin had been trying to save lives, the revelation of his condition made his position impossible.

Lupin's Farewell and Legacy

When Harry rushed to Lupin's office to plead with him to stay, he found the room half-packed. The Grindylow's empty tank stood beside his battered suitcase. Lupin was poring over the Marauder's Map, which he had retrieved from the Shrieking Shack. He returned both the Invisibility Cloak and the map to Harry, stating that since he was no longer his teacher, he felt no guilt in giving them back. He acknowledged that he and his old friends—Moony, Wormtail, Padfoot, and Prongs—would have wanted Harry to find the secret passages. In a final, poignant exchange, Lupin expressed pride in Harry's progress, particularly in mastering the Patronus Charm. He confirmed that Harry's father, James Potter, had always transformed into a stag, which was why they called him Prongs. Dumbledore arrived to inform Lupin that his carriage was at the gates. After a brief handshake with the headmaster and a final nod to Harry, Lupin left, his departure a direct consequence of the prejudice that had shadowed his entire life. The news of his resignation cast a pall over the end-of-term celebrations, with his students universally miserable about losing the best Defense Against the Dark Arts teacher they had ever had.