Freya

Freya is the Norse Vanir goddess of love, beauty, gold, and sorcery. She is a part of the Vanir tribe, twin sister of Frey, mother of Blitzen, and the ruler of Folksvanger - one of two places where Norse warriors go after death (the other being Valhalla).

The Sword of Summer
Magnus and Blitz first meet Freya, when they accidentally travel to her realm - Folksvanger. There, in the hall of Sessrumnir they meet the goddess who is reveal to be Blitz's mother.

Personality
Freya is a bright and helpful woman, very loving towards her family. However, she can quickly change her demeanor and become really intimidating, to the point where Magnus had a mental image of her riding into battle alongside the Valkyries.

Appearance
Her nephew Magnus describes Freya in The Sword of Summer as 'the most beautiful woman [he has] ever seen'. She looks around her twenties, and is surrounded by an aura of golden radiance which serves as the source of power for the entire Folkvanger. She has long, blonde hair, falling down her shoulder on one side, and sky-blue eyes.

She wears a white halter top, a knee-length skirt with a golden belt, which also sheathes her knife. She also wears a lot of jewelry.

Trivia

 * Freya's Greco-Roman counterpart (in terms of abilities) is Aphrodite/Venus, who also frequently wears quite a bit of jewelry.
 * She is also similar to Hecate/Trivia as she is a goddesses of sorcery and magic.
 * Friday was named after either her or Frigga.