The Saga of Tanya the Evil, Vol. 1 (light novel)

At the very edge of the front lines stands a young
girl. She has golden hair, blue eyes, and pale, almost translucent skin. This
girl soars through the skies, mercilessly cutting down her enemies. She barks
crisp orders with the unmistakable voice of a child. Her name is Tanya
Degruechaff.But her true identity is that of a 40 year old Japanese elite
salaryman who was forced by god to be reborn in the vessel of a little girl who
must live in a tumultuous world racked by war. Concerned with being
ultra-efficient and desiring self-promotion above all else, Degurechaff will
join the ranks of the Imperial Army's Military Mages and become one of the most
feared existences in this new world...