Iku Iku Succubus

Tanehisa Busujima is a middle-aged university professor well known for his lack of restraint and speaking his mind (for better or worse). His compulsions have put his job in jeopardy. The university's president provides him with a lifeline, though: Serve as an instructor for study abroad students from the Succubus Kingdom!

Not present anywhere in the Human Realm, the Succubus Kingdom is located in an entirely different world known as the Dream Realm. This begs the question: why are there study abroad students from another world attending a university in Japan?