Yesterday's post was about Hikaru. So, this post will obviously be about Koaru Hitachiin. Koaru is the younger of the two Hitachiin twins. He is more level headed and mature than his older brother, but becomes more mischievous when he is with Hikaru. Koaru also knows how important it is for both himself and Hikaru to become individuals, instead of being two parts of a whole. They both are very close to one another, and have been since they were young.