Becoming a Magical Girl

[Slightly depressing, 1v1 with a twist, slightly angsty but sweet] She's an agent, an idol, and once the "older brother." Now, she can only disguise herself as a man, struggling to maintain the last vestiges of her brotherly dignity. Until... she sees her younger sister standing in front of her, holding an exaggerated support sign, her eyes sparkling. She's dumbfounded. I'm your older brother!