Frey rose to the skies and lifted her spear as if to signal something from the distance. A bright flashing light suddenly illuminated the skies. Silhouettes of different female warriors started appearing, but they were not truly present.
The spiritual avatars of the Valkyries are all sent to aid Frey who is currently being possessed by the Goddess Freyja. All of the Valkyries appeared in the sky, but they are only spiritual entities made using the mana of the one who summoned them.
Frey's mana immediately went to zero upon using the skill that she can only do if her Passive skill called The Judge of War has reached a thousand stacks. This does not normally happen as battles would often finish before she reaches that number of stacks.
It is only this battle where she went up against a literal god, who got degraded to a demigod, that made her reach the required number of stacks. A skill that can also only be sued when the Goddess Freyja is descended on her body.