She is the character from Date a Live series.
She is the Head Analyst aboard Fraxinus and a non-certified medic who can perform simple first aid tasks.
Reine is a highly intelligent and rational woman. She is the Analysis Officer of the Fraxinus’s crew and the assistant homeroom teacher of Shido's classroom. She is also the only member that could be considered "normal" among the Fraxinus's weird crew. Reine also acts as an unofficial aide to Kotori Itsuka, the commander of Fraxinus, due to the fact that the vice-commander acts like an idiot most of the time or is ignored by Kotori for being an idiot.
Beautiful and intelligent, her only flaw is being sleep deprived, since she doesn't seem to sleep much. Reine transfers into Shido’s school, Raizen High School as the school's new physics teacher when Shido joined Ratatoskr. Reine usually gives the best advice or opinions out of Ratatoskr's crew during both the Fraxinus crew's operations to seal Spirits and normal circumstances.
It is revealed in light novel that she is the enigmatic entity known as Phantom, and later the doppleganger of Spirit of Origin Mio Takamiya.