Rosia is a fictional character from the anime series Show by Rock!!, a vibrant and colorful show that blends music and adventure. Rosia is the charismatic and cunning lead vocalist of the band Criticrista. Known for her distinctive style and pink hair, she often portrays an adorable yet mischievous persona. In the series, Rosia plays a pivotal role as both a rival and an ally to the main characters, showcasing her musical talent and ambition while navigating the challenges of the music world in the fantastical realm of Midi City.