The "evil" Slytherin... A Karlnapity story (first year)

When a young boy named Karl was invited to Hogwarts to become a wizard, but what happens when he is put in Slytherin, other start to assume that he is a bad and evil person, they pick on Karl thinking he's the classic snobby and evil Slytherin, what happens when the bulling starts getting more... violent...?

Sapnap a brave Gryffindor was bullied when he was younger by other kids mentally and physically, what happens when those same kids go to the same school Hogwarts and become Slytherin? He is filled with rage and to make sure he doesn't get the same treatment again he makes a certain Slytherin, wish he was never born...?

Quackity, a Ravenclaw, was always looked down upon by his family for not being a Slytherin, hated his family, his father and mother, who neglected him for just being a Ravenclaw, he joins sapnap and making a Slytherin wish he was never born...

Poor Karl has to suffer with the bullying all because other Slytherin's had made Sapnap and Quackity feel like they were all "evil" the bully starts when they are all 12 but when will this torture end for Karl...?