The Saga of Tanya the Evil, Vol. 4 (manga)

Having no candidates was Tanya's ultimatescheme to forestall a new project that would send her to the front lines. But her plan backfires after waves of applications from promising young soldiers flood the office. Just when she thinks things couldn't get any worse, the Elinium Type 95's mind contamination begins to take effect on the fledgling captain who-before she realizes it-is now the official leader of a battalion.