A Light Novel based on the Cult Classic Action RPG Tales of Phantasia.

It tells the story of Wynonna Pickford, an expert archer in the traveling magic troupe, who witnesses a strange light in the Valhalla plains, north of Midgards. Immediately afterwards, she is caught in the shockwave of the light, and finds herself teleported in front of a strange old castle. There, she encounters a mysterious man named Daos...
This is a pre-story for Namco's popular RPG "Tales of Phantasia" in which we discover how Daos come to reign as the Demon King!

(Source: Kadokawa, translated)