Strike Witches
A ninth manga titled "Strike Witches: Erica Hartmann 1941" (ストライクウィッチーズ エーリカ・ハルトマン１９４１) was serialized in Comp Ace between March and September 2016. The manga is a prequel story for Erica Hartmann, following her early days in the Karlsland JG52, three years before the start of the Strike Witches anime.