Kaoru Hitachiin is a devious and childish first-year student who greatly enjoys toying with his fellow Host Club members, Haruhi and Tamaki (whom he often calls "My Lord"). He and his older identical twin, Hikaru, are "little devil" type hosts who put on an act of "forbidden brotherly love" (with Kaoru as the uke) to draw in their clients. Unlike Tamaki, the Hitachiin brothers are wholly calculating in their customer relations; however, this is because of their deep dependency of each other and a reluctance to let anyone into their world. Hikaru and Kaoru share a deep emotional bond, which was forged through a lonely childhood and through the fact that no one could tell them apart without looking at the parting of their hair (Hikaru's hair parts to the right; Kaoru's parts to the left). Since Haruhi is the first person that can truthfully tell them apart, they greatly treasure her friendship. Haruhi has stated that Hikaru and Kaoru have their differences, despite being identical twins. Of the two, Kaoru is nicer, more mature, and considerate of others.