Kuroinu: Kedakaki Seijo wa Hakudaku ni Somaru Episode 6

In the land of Selenus, a great war has raged for hundreds of years between the allies and the demon army. Now, at last, victory for the allies is within sight. The allies commission Vault and his mercenary troops as the vanguard of the final assault.

The attack succeeds, but, Vault and his people have plans of their own…