|Japanese name:||常陸院 光, 常陸院 馨|
As they get to know Haruhi better, they start to care for her deeply, especially since they discovered that Haruhi can tell them apart, something that no one has ever done before. When they were very young, a maid they were very fond of betrayed their family by trying to rob them. The twins made her play the "Which one is Hikaru?" game and promise that she wouldn't rob them but she broke her promise and told them that no one would ever be able to tell them apart. Tamaki Suoh, however, in their last year of middle school, repeatedly followed them tossing out random guesses as to who was Hikaru and who was Kaoru to get them to join the Host Club Showing his intuition and false reasons each time. Kaoru is more mature than Hikaru as he understands and handles situations better than the narrow-minded Hikaru. Finally they crumbled, and decided to just try out the Host Club, and thus took a step towards a wider world, also developing a deep bond with Tamaki (who, eventually, does learn how to truly tell them apart). For this reason, they were originally cynical to the world before joining the Host Club, believing that anyone who is not the other twin cannot possibly compare to their bond. Additionally, because their parents were often away, they developed a deep dependence on each other through loneliness, but seem to open up to others recently, thus their relationship with Haruhi is a large part of their life.