Cozy was born into a family where the parents were both unicorns and she had older siblings that were also all unicorns and she was the only pegasi and also the youngest. Cozy's parents would take the children regularly on raids and other illegal stuff, using lies, cuteness, and magic to get what they wanted, and always thought it was so fun, raising all of their children to also think this stuff was fun. Since Cozy is a pegasus, nopony in her family thought she would be able to do raids and that other stuff nearly as well, so she always had the least important things to do, and sometimes got left behind entirely. Her siblings always had that sense of superiority over her, and Cozy got frustrated because she knew her siblings and her parents were having fun, and she wasn't able to go when she knew she could help so much. So, she hatched a plan. Her parents told her all about Twilight and her friends and how they defeated other villains, and Cozy knew that Ponyville would easily fall for her acts, especially since she didn't have magic. How was she a threat? Then, she could get close and figure out a way to have lots of fun while never being suspected. So, she snuck out and went to Ponyville. When she went to the School of Friendship, she realized she was going to need some help getting information, so she set up an act in the hope that somepony would feel sorry for the poor little filly crying all alone and come help her. The CMCs came and helped her, and she learned about the magic of friendship through them, and how powerful it was, and she decided, "Hey, I'm really good at tricking ponies into thinking I'm a sweet little filly, I can use that to get me lots of friends."  She began to think about how fun it would be to have that much power, but she knew she was just a pegasus, and even if she had all the friends in Equestria, alicorns and unicorns would still physically be more powerful. So she stuck around in the School of Friendship, gaining friends, building trust with the professors and head mare and student counselor, and she constructed a plan. "Unicorns and alicorns are only powerful because of magic, which is what other creatures also use as power, and if I got rid of all the magic in Equestria, and I continued with my original plan, I'd be the most powerful being in Equestria! But, I don't know how to do that, and I doubt any of Twilight's books would have it, and even if they do, I can't waste time, and I can't ask Twilight or she'd get suspicious. I need somepony with experience in magic." She thought of Tirek first, and started sending him questions with letters, and she was very happy when he answered them, so she sent him some more,until she had all the info she needed. All she needed now was a place to put the artifacts where nopony but her would know. She saw that the Student 6 were close friends, and wondered if she could do something to make their friendship=power go away, so she decided to create a little tension among them. Then when they found the underground chamber, she knew that was the perfect place for her artifacts, but when the Young 6 mentioned telling the professors, Cozy needed to stop them or she'd need to find another spot and wait even longer for her plan, so she improvised a quick excuse for her to not want them to tell the professor, and the excuse worked. Now everything was ready.