Alyu Lux (or Allu Lux) is Monica Lux's older sister. Both sisters work as rhythmists, sacrificing aspirations to join the Court Orchestra to fund healing their mother's blindness. Extroverted and talkative, Alyu possesses fierce protectiveness towards Monica, though her harsh manner can seem rude. Her percussion expertise contrasts Monica's singing, forging them into a "Sibling Yin-Yang" pair. Alyu sports red hair, red eyes ("Curtains Match the Window"), youthful freckles, and typically wears a bra, sleeveless vest, and pants ("Stripperific"). She demonstrates physical combat prowess, incapacitating a soldier with a wrestling move after Pony executes a groin attack.