37 is a playable character in Reverse:1999. She is one of the member of Apeiron, an all-arcanist society that practice Pythagoreanism that believes all is explained by number, including themselves. Obsessed with the belief, 37 is indifferent to the material world, and only cares about numbers and shape of forms. She was gifted that she can accurately predict someone's exact number. She also a friend of Sophia.
She has blue long hair and blue eyes, and wears ancient greek clothes.
She is voiced by Emily Stranges in English and Iguchi Yuka in Japanese.