Severus T Snape

That morning hadn't started well at all, with insults and taunts from students in his own house, Slytherin. After all, Lucius wasn't there to "look after" him, and his other "friends" thought he should learn to deal with his bullies on his own. But the day only got worse as classes went on. Sirius ruined a very important potion in the middle of class, James stole his homework, forcing him to redo it, Peter helped Sirius and James, and Remus, though he didn't do anything... simply diverting attention also made him an accomplice. Now, in front of all the other students from the different Hogwarts houses in the school's main garden, Severus was hanging upside down without his trousers. It was the worst prank the "Marauders"—James, Sirius, Peter, and Remus—could have played on him. It not only embarrassed him, it humiliated him, it broke him. James spun Severus around, while Sirius and Peter encouraged people to mock him... and Remus just stood by. He looked away, but suddenly a spell knocked James down, causing him to lose his concentration and the spell that had Severus upside down to release him...with slow, tense steps walked "Yori Black," Sirius's younger sister, a Hufflepuff, who detested her older brother's arrogant and rude attitude...now she stood before her brother and friends, protecting Severus...the first act of genuine kindness he had ever received

Sirius: angrily looks at Yori for ruining the joke. "What's wrong with you?! Why are you helping him?! Can't you see he's a Slytherin?! He's the bad guy!!! "

Yori glares at Sirius and points her wand at him menacingly, ready to protect Severus. "Since we were young, we've been taught the difference between a hero and a villain, good and evil, a savior and a lost cause... but this time the only difference is that you're telling the story... you're the bad guys this time! Dare to come near me."