Tatsuya Kitani is a Japanese musician, singer, lyricist, composer, and arranger. He is the bassist of the three-member band sajou no hana. He was also active as a Vocaloid producer under the name of "Konnichiwa Tanita-san". The affiliated office is Smile Company, and the affiliated label is Echoes under Sony Music Entertainment Japan. His official fan club is "Club Unreality".