Centuries ago, he was in a relationship with a princess, and he vowed to marry her after a war, but ended up dying. However, he left Kyoukai before getting to be reincarnated, and lingered in the living world looking for the princess.
One month ago, he spotted a Sankai High student named Kaori Himekawa in Kyoto, who came on a school field trip, and believing her to be the reincarnation of his lost love, would stalk her since then and constantly give her sake in her dreams whenever she falls asleep.
As Kaori was frightened of him and could hardly get any sleep, she was advised to use the instrument shelter. Rinne would contain him and allows him to speak with Kaori in person, and ask her to grant his wish to have a ceremony with her so he may pass on. However, he would not pass on for it is revealed that she is not the reincarnation of the princess. But thanks to Rokumon, the real reincarnation of his lost love is revealed to be Suzuki, which leaves Ochimusha disappointed and resolved to pass on.