Werebeasts of Hel — Asa Drake

Bloodsong #3

Bloodsong faces the greatest enemy she has ever known -- her own son, Lokith, the demon of Helheim. Once destroyed by his mother, now Lokith is back with a vengeance, allied with the Death Goddess hel and supported by a vast army of her fearsome Death Riders. Armed with only her sharpened sword and the dark-beast powers that are her heritage, Bloodsong must face her son's blind fury and battle the foul forces of Hel as she searches for an ancient long-departed army that may be her -- and the Earth's -- only hope...

Reedited as "Warrior beast" by C. Dean Andersson.