|Alias||Witch of the Void (空隙の魔女, Kūgeki no Majo)|
|Race||Human (Attack Mage)|
|Occupation||Teacher, Attack Mage, Security Supervisor|
|Base of Operations||Itogami Island|
|Anime Debut||Episode 2: Right Arm of the Saint II|
|Manga Debut||Chapter 2: Watchdog|
|Novel Debut||Volume I: Right Arm of the Saint|
|Japanese Voice||Hisako Kanemoto|
Natsuki Minamiya (南宮 那月, Minamiya Natsuki) is an English teacher at Saikai Academy and is one of few people who knows that Kojou is the Fourth Primogenitor. Outside of school, she is a high ranking attack mage and is referred to as "Witch of the Void". It is revealed that she is the guardian ("the jailer, the door, and the key") of the legendary magical prison that houses the most dangerous supernatural criminals with her body being sealed inside the prison and while the version of her that appears outside of the prison is merely an illusion. In the Banquet for the Observers, Natsuki's memories were taken by Aya. She teleported herself near the Keystone Gate where she instinctively recognized Asagi who then after took care of her and gave her the temporary name, Sana. After defeating Aya, Natsuki regained back all of her memories.
Natsuki is 26 years old but appears to be much younger because she has been in an enchanted sleep for 10 years of which have made her body not age. Her appearance prompts Kojou and Asagi to call her Natsuki-chan, although she repeatedly tells them not to. She has dark blue eyes and has long black hair with a fringe and long bangs on either side of her face. She is usually seen wearing a black gothic lolita outfit and carrying a black parasol. While undercover as a student in order to discover who was molesting her students on the monorail, she wore the standard Saikai Academy uniform, plus thigh-high socks and a school bag.
She has a childish personality and is very stubborn, but she is very caring as she took Astarte to a festival so that she could enjoy and finally Astarte started showing expressions of delight. She also likes to tease people which is shown when she teased Kojou about getting aroused around Yukina in public.
Right Arm of the SaintEdit
Natsuki checks Kojou's make-up tests where Kojou inquired her about the Lion King Organization. She pulls him by the ear and asks him where he heard about it. Kojou lies that he just heard from some rumor about it but lets him get away with his actions. Later, she catches Kojou and Yukina in an arcade but when she approached them a sudden explosion distracted her, making them have a chance to escape though leaving the Nekomatan they won at the arcade. The next day, she calls them and announces about what they did after running away last night which caused the boys to have a wrong impression. The trio then talk about the explosion last night and she then says that a demon hunter is on the loose. She gives Yukina her Nekomatan. Later, she investigates the scene of the explosions.
Emissary of the WarlordEdit
Natsuki fought alongside Kojou, Yukina and Astarte against the angel-like beings.
Labyrinth of the Blue WitchEdit
Banquet of the ObserversEdit
When she was attacked by the escaped prisoners of the legendary magical prison, she escaped by teleporting herself to a place where one of her own students, Asagi was present and reverted to her childhood form. She was robbed of her memories and powers by Aya. Natsuki later regained her powers and memories by drinking Kojou's blood when he bled in the bath. When she regained her powers, her guardian soldier, Rain Gold was summoned but because Rain Gold's attacks could cause potential damage to Itogami Island, it is always sealed and summoned in an imperfect state.
Return of the AlchemistEdit
Night Lord of the Blazing LightEdit
Known as the "Witch of the Void", she is a powerful attack mage who is strong enough to fight Kojou, Yukina, and Kiriha at the same time.
My name is the Void. I am she who reduces broken vows to ashes by my eternal fires. Tear off your yoke of black blood, and return to where you belong! Offer your sword to the blue maiden, the blessing of your honored soul!
Waga na wa kūgeki. Eigō no honō o motte haiyaku no noroi o yakiharau mononari. Nanji, kuroki chi no kubiki o saki, arubeki basho e kaere. Mitama o megumitaru aoki otome ni ken o sasageyo!
|Space Manipulation||Capable Of Manipulating Space, This Includes Teleportation.|
|Chain Projection||Natsuki is able to create magical chains.|
|Prison barrier||This is the magical technique used to seal magic criminals within the prison barrier. She is the only person that can use it. If she is killed, those held within the prison barrier will be set free.||200px|
|Guardian Summoning||Her guardian is Rain Gold, a knight dressed in golden armor. Because its immense power could potentially cause tremendous damage to Itogami Island, it is always sealed and summoned in an imperfect state. In Volume 11, it was strong enough to seal Regulus Aurum for a period of time.|