According to a game by Lune.

This is actually the sequel to Ride with the Valkyrie.

Goddess of war %u2014valkyries%u2014 tend to be fierce and invincible in battle. But they possess the defect for being drawn to normal male humans, that this inhabitants from the overworld noticed and chose to use in their advantage: not only to win battles, but to capture some valkyries and using them as sex slaves. Freya was captured along with the devils are now able to see in which each goddess is, resulting in disaster.