Rumi

 is a side character in Queen's Quality. She is the childhood friend of Ataru Shikata.

Queen's Quality
Rumi is first introduced when Ataru's hidden memories are unlocked by Fumi and is only seen through flashbacks. Rumi was an orphan who was at the same orphanage as Ataru was and quickly became his 'savior', saving him from the constant bullying he faced, even though this also contributed to her own harassment and disdain from others. However unbeknownst to the children, they were actually being used for experimentation to develop special abilities and were constantly fed pills. Most of these tests were conducted and overseen by Dr. Hijime. Due to Dr. Hijime's favour toward Rumi and Ataru, Rumi was predetermined to be a Queen and because of the regular undergoing of experimentation and the constant negativity surrounding her, Rumi came into that power, though it corrupted her greatly. She murdered the rest of the students in the orphanage when they came to attack her for turning into a monster by telling them to kill themselves or attack one another. Due to her rough upbringing, abusive parents and teachers and the constant bullying, Rumi's hellbent attitude on getting 'revenge' to once make the world a kinder and nicer place, seemed to have shred the last bit of her humanity.

When Ataru sees what she has done and how maniacal she had become, he begs her to stop, hugging onto her. This awakens the last bit of her true, kind self up again and Rumi tells Ataru to stay away from her, for she has become a monster. While trying to think rationally the corruption in her mind gains control again and she battles with the urge to kill Ataru and wanting to truly be able to protect him to the end. She climbs onto the balcony of one of the orphanage's rooms and thanks Ataru for keeping his promise of 'telling her off if she becomes a bad Queen' before jumping off, killing herself in front of him (though Ataru himself doesn't at this moment realise she is truly gone).