Takeru Satoh
The "Double-Action" line of songs are (initially) a series of duets sung by Ryotaro Nogami and his Imagin partners (actor Takeru Satoh and the voice actor for the Imagin) and are used as the ending theme or the song played in the background of climactic scenes whenever that Imagin's form of Den-O is used. Every CD that a "Double-Action" song is released on also features a version of the song with sound bites of the character's dialogue throughout the song.