A grey cat transient from the world of Utopia with heterochromia. After a long and meandering journey, she is now attending Shinjuku Academy's elementary school department. Quantum shows great expertise in advanced physics and draws heavy attention from educators for gifted students. Sometimes she says sassy things, but at her core she's a friendly, lonely soul. Quantum is a test subject for Utopia's acceleration technology, just like a senpai at school who likes to garden. 