[4] Indigo la End released their debut extended play Sayōnara, Subarashii Sekai in April 2012, though the independent label Space Shower Music.

[5][6] Kawatani continued to release music with Indigo la End, with their second extended play Nagisa nite in September 2012 and their first album Yoru ni Mahō o Kakerarete in February 2013.

[12] The band's debut album Miryoku ga Sugoi yo (2014) reached number four on Oricon's album charts, and their second, Ryōseibai (2016), reached number one, after several commercially successful singles released in 2015: "Watashi Igai Watashi ja Nai no", "Romance ga Ariamaru" and "Otonatic".

[13] In 2014, Kawatani composed songs for musicians outside of his two bands for the first time, when he gave the boyband SMAP two songs for their album Mr. S. Kawatani worked with the band again in 2015, on their single "Ai ga Tomaru made wa", and has also worked with Tomohisa Yamashita, and the girl group Team Syachihoko on their single "Shampoo Hat" (2014).

[16] In December 2015, Shin-Ei Animation had contacted Kawatani to ask him to write the theme song for the film Crayon Shin-chan: Fast Asleep!