I Couldn't Pay Off My Student Loan, so I Had to Work Part-Time as a Magical Girl

"Brother! Let me tell you a secret...!" "In this world, only girls with pure wishes can be chosen by the will of the world, so I, my sister... Will transform into a magical girl!" My sister, who was in the advanced stage of her second grade of chuunibyou, swore loudly. Su Bai, who was worrying about his studies, just wanted to say, destroy them all. But when the monster suddenly appeared, he followed the magical girl transformation manual made up by his sister, assumed a shameful posture, and recited the second spell—— In the bright light, the magical girl chosen by the will of the world was born.