News Retracted
According to GaGaGa Bunko official blog, the announcement of the anime movie was a false information. The start of the manga adaptation is correct.

Source: GaGaGa Bunko official blog

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According to Web Sunday, Tanaka Romeo's light novel "AURA ~Mayuin Koga Saigo no Tatakai~" was announced to get a film adaptation. It will be premiered in 2012. Its manga adaptation by Hoshino Koichiro will be serialized in Monthly Shonen Sunday Super from February 2012.

Cover art of AURA novel

Synopsis:
Sato Ichiro once called himself 'Maryuin Koga' and behaved as if he were a hero in a fantasy world (cf. Hououin Kyouma in Steins;Gate). His strange behavior caused his classmates to bully him and he left the school. At his new school, he tries to behave like a normal boy, but one day he meets a girl who cosplays with a blue cape. She calls herself "a researcher traveling from the outer world to search for the 'Dragon Terminal'". At first, Ichiro rejects the girl, Sato Ryoko, because her behavior reminds him of his embarrassing past, but he changes his mind after seeing her getting bullied. In order to bring Ryoko back to real life, Ichiro accepts her and his past and begins the final battle as Maryuin Koga.

Source: Web Sunday