Fluidity system

Calla was never able to see her system even thought it passed coming the age. Why was she in this system school if she didn't have one? Even if she would get it now, she would be the weakest of them all... Or so she thought. Even without a system, no one came to seek trouble with her. So why did everything change when this fluidity system appeared? She was happy without one. Now she has to do the tasks and beat people up. /Cover is not mine/