Kaoru Asahina (朝比奈 薫, Asahina Kaoru) is a supporting character in Sekai-ichi Hatsukoi. His first appearance is from Junjou Romantica. Although he is a supporting character, Kaoru has his own episode.
Asahina is typically seen wearing a black suit with either red or blue ties.
Asahina has known Isaka since childhood. His father had lost everything and attempted a family suicide by driving off a high curb. His family survived the attempt. After learning about their situation, Isaka's parents hired the family. Ashina was deeply grateful to Isaka's father for saving his family. Asahina became best friends with Isaka. He promised Isaka to be by his side. Asahina has been Isaka's assistant for years after Isaka's father stepped down.
Kaoru is Ryuichiro's childhood friend, assistant, and lover. Kaoru is very polite around Isaka, even up to the point where he calls him "Ryuichiro-sama". Before Kaoru met Ryuichiro, he was involved in a car accident which his father attempted family suicide. Kaoru was Isaka's father's assistant before Isaka took over.