Young
When Margarita was a young girl she didn't have any friends. Not many eight year old girls wanted to play with a poor girl who could make freaky things happen. Margarita's father was in jail for scamming and her mother worked as a waitress in a bar. At her age Margarita didn't know she was a witch and instead believed the other girls when they told her she was weird and didn't fit. Her mother called her a freak, for she was a muggle and had hated magic ever since her father was taken away from them. So instead of playing with her classmates, Margarita played with bugs and beetles and had fun studying them. The other girls tried to annoy Margarita by squashing the bugs, but stopped doing this, as one day, the bugs suddenly attacked them. Of course, Margarita had nothing to do with that.
Gossip
Halfbloods were rarely sorted into Slytherin, but Margarita was one of the few exceptions on that rule. Determined to be popular at Hogwarts, contrary to her old school, she had created a new 'Rita'. The new Rita had curly blond hair, which was dyed and curled and fashionable robes, which she had made herself. Rita also had a big attitude, which Margarita copied from one of the other girls in her year, Bellatrix Black. The Rita that Margarita had created was beautiful, popular and mean. She decided that the character Rita would be sorted into Slytherin and convinced the old sorting hat of doing so. One thing that Margarita had always been good at was convincing other people. The sorting hat pitied her and decided against his judgement to put her into Slytherin. It was there, in Slytherin that she discovered her biggest talent. While being fairly good at transfiguration and Defense Against the Dark Arts, Rita excelled in the art called gossip. She found out that an interesting story made people listen to you, whilst knowing their secrets made people fear you.
Vengeance
At first Rita only used her talent to make her more popular. She would make up stories about herself and the amazing things she had done. The first time she used gossip for revenge was in her fourth year. She walked into a corridor to find Andromeda Black kissing a boy from Huffelpuf. Slyherins rarely dated outside their own house and never even looked at the Huffelpufs. To say that Rita was surprised would be an understatement. The Rita that had been invented in the first year had gotten meaner and smarter. Telling this secret would only lead to creating an enemy. Rita was smarter than that, so instead manipulated Andromeda into doing things for her. Rita would have been content with things if it hadn't been for Bellatrix. She had kissed a fifth year Slyherin that she knew Rita had a crush on. Rita sought revenge and decided that humiliating Bella by telling everyone she had a muggle-loving sister would be the sweetest revenge.
Quick-quotes quill
It was during Rita's fifth year that she found a companion who loved gossip just as much as she did. She charmed a quill into writing things down what she said. It was an easy way of doing her homework, and it didn't damage her nails either. She didn't discover the damage that her quill could do until she accidentally dropped it into her cauldron while she was making a delusional potion. After that the quill exaggerated and sometimes even wrote down lies. At first Rita was annoyed at it, but then she realized the full potential of the quill. A new, true journalist was born.
Magazine
After school Rita decided to put her hobby into her job and applied for a job at the daily prophet. She didn't get the job because her boss went to Hogwarts with her and remembered the lies Rita used to tell. Rita then wrote a letter to the chief editor and complained about the unfairness of her rejection. Just because someone spread a nasty rumour about the girl dating one of the professors, didn't necessarily mean that Rita had spread that rumor. The chief editor didn't like Rita, but recognized a good gossip journalist when he saw one, and thus he gave her a job.
Misunderstood
Rita didn't hate Hermione because she called her a godawful person. Rita simply hated Hermione because the girl was confident and had friends. Even in her final years, when Rita had been popular and feared, she had always been worried about what would happen when her friends would find out about her heritage. She never had any true friends because they would always worry about what Rita could do with the secrets they told her. Rita was able to see the person she could have been in Hermione and it made her sad. For a small moment she allowed the nervous, shy Margarita to mourn her past. Just for a small moment, then she began to write another article, hoping it would make her forget it. Margarita may have created Rita, but it was Rita who had destroyed her.