Haruki (White-haired) and Haruko(Black-haired) were the twins born to be the reflections of the other one. They often hang out with each other, though one day their friend, Hitomi, created a portal to a dimension called "The Second Life"(often known as Ikoma) in order to restore the balance in their dimension, for both Haruki and Haruko of Ikoma died. Hitomi tricked Haruko and pushed her into the portal, making Haruki think that her twin died, she never became the same again, but she promised to avenge her sister. (I am planning for about 10 books! Please support :D )