Wada Kouji
Information:
After debuting in 1999 with a theme song for the anime "Digimon Adventure", Wada would have many of his other songs features as theme songs in this anime.
In 2003, he would announce that he was ceasing his activities at a concert. This would not last too long though, as he would resume live performances in 2006, and return with more Digimon theme songs (as well as some for other anime series).