Louise Colette Célestin is the twin sister of Lisette. She is as much of a child prodigy as her sister is.

And just like her sister, Louise took an interest in playing the violin at a young age. They made quite the musical duo at their local Army post, turning into an overnight sensation at the ripe age of 7. Their parents created an all-female musical troupe called the 'Célestine String Quartet'. The quartet consisted of the twins, their mother, and their caretaker, with their father acting as the group's manager. The quartet sadly came to an end when Louise fell to her death during a family vacation to Niagara Falls.

Before her untimely death, Louise exhibited other gifts. She was a Synesthete like her sister, although showcased different synesthesia than what her sister had. While they both shared chromesthesia and personality-color synesthesia, Louise had the following other synesthesia: grapheme-color synesthesia and spatio-temporal synesthesia.

Louise was also the more extroverted of the two, often making friends easily and feeling energized by crowds. When Lisette met Carmen, she reminded her a lot of her late sister. Ultimately the two went on to have a sister-like relationship.