Senjou no Valkyria: Gallian Chronicles

The story is set in a fictional version of Europe in 1930, in the country of Gallia. Because of its abundance of ragnite ore—which can be refined into a powerful fuel—it has come under attack from the East European Imperial Alliance, which itself is engaged in war with the Atlantic Federation.
The story revolves around Gallian soldiers led by Welkin Gunther, son of Gallian war hero General Belgen Gunther, in a bid to reclaim their war-torn neutral nation from Imperial Alliance forces and drive them off from Gallian soil after they had launched an invasion into the country.