Mari-sama to yakyu ken shite mita - Oneshot

[MangaDex]

 

[Threacon]

who's that in ooarai uniform

 

[oniichaniscute]

who's that in ooarai uniform

this is a doujin of "Girls und Panzer", after some research i couldn't find the character in question. you can probably find her by checking the characters in the series!