Featherine Augustus Aurora

Featherine Augustus Aurora (フェザリーヌ アウグストゥス アウローラ) is an extremely powerful witch who can freely rewrite reality. She appears in the last three episodes of as an observer and antagonist. She also appears in as the being Eua.

Background
Featherine is a godlike witch whose near-infinite life and nigh-omnipotence require her to wear a memory aid device which maintains her name, appearance, and personality across her existence. Featherine sees even high planes of existence such as Purgatorio as a script which she can modify at will.

In, she is suddenly spawned into existence when Satoko interacts with a broken horn in the Saiguden. As such, she has no name until she asks Satoko to name her, which she accidentally does by mumbling in confusion.

Appearance
Featherine appears as a tall woman with long, dark purple hair stylized in a hime cut. She wears an elaborate pink dress with multicolored highlights along with a green sash adorned with a ceremonial medal. She has a silver device that floats around her head that functions as a memory aid device.

Personality
Featherine acts in accordance with her status as a being of nigh-omnipotence and can be condescending to the beings who speak to her. Featherine claims that she needs to constantly think or else she will perish. She often refers to human beings as "child of man."

Dawn of the Golden Witch
Featherine appears to Ange Ushiromiya in the form of Tohya Hachijo. After Ange deduces that Hachijo is a witch, she reveals her true form. Featherine then asks Ange to serve as her miko and read her the story titled Dawn of the Golden Witch. As the two read, they form various theories as to what Battler's sin was.

Satokowashi-hen
Featherine's first appearance in is as an unnamed being in, wherein she appears to Satoko Houjou after Satoko interacts with an object in the Saiguden. She gifts her with the power to travel between fragments, similar to what Rika is able to do. After Satoko opts to view every fragment that Rika experienced, she gives Satoko the ability to loop alongside the same iteration of Rika as long as the two die shortly after each other. Some time later, she asks Satoko to name her; Satoko mumbles in confusion and she accepts this as the name "Eua."

Trivia

 * Though there is no confirmed relationship between the two, Featherine Augustus Aurora is strongly connected to Hanyuu from.
 * Featherine and Hanyuu share a similar appearance, specifically Featherine's dress and memory aid resembles Hanyuu's miko outfit and horns.
 * When roughly translated, the kanji in Hanyuu's name (羽入) mean "feather" (羽) and "in" (入), which, when put together, essentially make "Featherine".
 * The katakana that begin "Augustus" and "Aurora", "Au" (アウ), are the same as Hanyuu's catchphrase "Auau" (あぅあぅ). Bernkastel references this by referring to Featherine as "Auaurora".
 * Lambdadelta mentions that Featherine's memory device was damaged, resulting in a change in appearance and personality. Similarly, one of Hanyuu's horns has a crack in it.
 * When Featherine first appears in, she is wearing an outfit similar to Hanyuu's typical outfit.