Senjou no Valkyria 3: Tagatame no Juusou  

Valkyria Chronicles: Unrecorded Chronicles OVA, 戦場のヴァルキュリア3 誰がための銃瘡

The Second Europa War is taking place between Gallia and the East Europan Imperial Alliance. A group known as the Nameless are fighting against both superpowers and trying to find their place in the conflict. However, things become more complicated when one of their tank drivers, Gusurg, abandons them to fight for the Empire. After liberating a small town from the Empire, the Nameless encounter Isara Welkin, an injured tank driver from Gallias Squad 7 who is retreating after a failed raid. She pleads with Kurt Irving, the leader of the Nameless, to help her squad. The Nameless must now decide whether to remain hidden or redeem themselves by aiding the nation that labeled them as traitors.