Tenka Yatogami

Dark Tohka is ?.

Dark Tohka Becomes
Tohka is captured by DEM Industries at the end of volume 6, and on seeing Shidou ambushed and is about to be killed by Ellen Mira Mathers, she is filled with such despair que she transforms and goes on a rampage, attacking everyone in sight including Shidou. Westcott calls her transformed state the Demon King, que adding this transformed state is the current form of Spirits like her in the bordering dimension que they come from before manifesting in this world.

Appearance
Dark Tohka is a girl with pale skin, Black Plum hair, color of eyes lght purple.She wears a dark purple Astrall Dress which is somewhat similar to an armor.

Personality
His personality is almost unrecognizable, she does not show many facial expressions, she only responds with an attack with intent to kill any person or living being who is in your front.

Powers and Abilities
Demon King: Nehemah (暴虐公(ナヘマー), Bougyakukou, lit., "Tyrant Ruler")

After prolonged exposure to negative emotions when Shido was about to be killed, Tohka transforms into her other form, which is revealed to be her true form in the bordering dimension where she came from. She obtains Nehemah, a stronger version of Sandalphon, and her astral dress becomes much darker and more revealing.

Plot
Light Novel: Volume 6-7

Anime: Unkown

Trivia

 * Tohka's name reflects the naming pattern amongst Spirit characters. Tohka's name is written as 十香, with the character for "ten" composing her name. The "ten" in her name refers to the Tenth Sephira in the Tree of Life of Kabbalah, pertaining to "kingdom." The concept of "kingdom" is evident in her attire, which is a mix between the dress of a princess and the armor of a knight, and her weapon, which comes in the form of a throne.
 * Her angel's name (Sandalphon) was translated variously as 'Lord of extent of height", "Co-brother" and "the sound of sandals."
 * Tohka appears to be a glutton.
 * Tohka's name was given by Shido, based on the day of their first encounter, April 10, 2013.
 * In the anime, for the the first 2 episodes, Tohka's voice is kind of low pitched, but for the rest, her voice is like a normal teenage girl's. This could be due to the fact that she was experiencing life on earth for the first time or her childish personality.
 * In the anime, Tohka's most valuable item is a bread-like pillow which she won at a game center with Shido; this one is destroyed due to Origami's bullet. But in the later episodes, she has this same kind of pillow inside her room.
 * Tohka is the only spirit so far who has two Astral Dresses.
 * Tohka's threat level is AAA-class, but when she is Inversed it's increased to SS-class, the highest so far, surpassing the most dangerous Spirit, Kurumi.
 * In the light novel, Tohka adopts the school uniform from a nearby student. In the anime, she adopted it from a picture of Origami that Shido had.
 * In the light novel, Tohka learned the meaning of date before her first date with Shido, while in the anime, she learned about it after her first date with Shido.
 * Tohka's astral dress's name is Adonai Melech which means "(the Jewish) God is a king" in hebrew.
 * Dark Tohka sure is very similar to Saber Alter.