theme song to the 2016 smartphone game Ao no Kanata no Four Rhythm: Eternal Sky, was released in an AoKana vocal album on May 1, 2016, A final compilation album titled Mami Kawada Best "F" was released on November 22, 2016; the limited edition includes three Blu-ray discs featuring her music videos, a video recording of her final concert, and a documentary on her career and final concert. A video recording of her final concert was made available through streaming on D Anime Store's website. She made an appearance at NBCUniversal Entertainment Japan's 25th anniversary concert on February 3, 2018, where she announced her marriage to long-time producer Tomoyuki Nakazawa. She also wrote the lyrics to the song "Gravitation", which was used as the opening theme to the anime series A Certain Magical Index III; the song was performed by Maon Kurosaki. Although retired from professional singing, she remains active as a lyricist and occasional composer. Musical style and influences Kawada's musical style mainly fuses rock with trance. When Kawada debuted in 2001, she originally felt that the music she earned in her career was pocket money. She also felt happy that she could be based in Sapporo where she could be close to her family and friends, as well as to I've Sound who she felt was like a second family to her. After Kotoko made her major debut in 2004, I've Sound management began discussing the possibility of Kawada making a major debut. At first, she was hesitant because she felt that she would be thrust into the spotlight, but eventually she accepted the idea. For the first ten years of her career, she always felt that she was a beginner, but this began to change when younger singers made their debuts and began to treat her as an older sister. In an interview with Famitsu, Kawada related her experience writing the lyrics for "Joint". Kawada said that she was challenged in writing lyrics for the song, since her previous single "Get My Way" was different from her previous singles. Kawada would read the source material of every anime before writing lyrics for its theme songs. She named the song "Joint" because of Shana II theme of characters Shana and Yūji Sakai fighting together. In response to comments that the expressions in her voice were very varied, Kawada stated that she simply sings with the music in the