One of Eiden's clan members, Rei is a mysterious young man with silvery hair. Rather erudite, he's accompanied by a boreal owl of death known as "Father". Resolute in his beliefs, he will do what it takes to accomplish his goals. His nonchalance belies all kinds of secrets.

After receiving Eiden's letter, he journeys to the Dark Territory. But before the investigation can begin, he's pulled through a ripple in time and space and into another world.