In line with the game by Lune.

This is an alternate retelling of Ride of the Valkyrie.

After being captured from the demon king's army, Valkyrie Reia is going to be executed by Duke, leader in the Dark Knights. However, Ariya, wielding Odin's Gungnir, appears on the scene. With unmatched strength, she easily lays low the demons in this area. However, when she reaches the condemned, Reia unexpectedly steals Ariya's silver ring, the source of an Valkyrie's power.

Without her powers, Ariya is easily captured and in addition becomes Duke's prisoner...