Koutetsu no Vendetta Episode 0

Rain Yashima, after years of military service, feels frustrated by the Japanese army’s lack of offensive action and its technological disadvantage against the enemy, the Seventh. With the war seemingly unwinnable, she receives an unexpected opportunity. A girl gives her the ability to influence history, and Rain chooses to abandon her identity as a woman, dedicating herself to battle as a weapon of steel. Her solitary struggle begins as she takes on the war alone. The project originated as doujin shorts by Thumbnail, with an anime adaptation announced in 2009 by Ankama Japan. Production stopped in 2011 due to the company’s dissolution but resumed in 2013. Only one episode, titled "Episode 0," has been released to date.