Kōji Wada

was a Japanese pop singer. He was best known for performing theme songs for several installments of the "Digimon" anime television series. His best known singles were "Butter-Fly", the theme song of the anime "Digimon Adventure". 
His nickname is "Immortal Butterfly Anisong Singer" (不死蝶のアニソンシンガー).
On April 3, 2016, Wada died suddenly from nasopharynx cancer-related problems in Tokyo, aged 42.