Valkyrie Profile: Covenant of the Plume

The plot focuses on the journey of Wylfred, whose need to exact his vengeance by slaying the Valkyrie is great enough to attract Hel, Queen of the Underworld, with whom he makes a pact with for power. By order of the pact, Wylfred must sacrifice the lives of other humans, including women and children, to obtain the dark power necessary to slay the Valkyrie. In his journey, Wylfred learns whether or not taking the lives of others is justifiable for his cause. (Valkyrie Profile Wiki)