Tanaka Koki, or Koki, former member of KAT-TUN. He was recognized as the rapper for the group and had a hip-hop-influenced style.
Koki wrote most of the rap lyrics for the group's songs as well as his solos by the pen-name of "JOKER".
He had been acting quite a few dramas and also in the stage play 'DREAM BOYS" with ex-group member Kamanashi Kazuya in Year 2007, 2008 and 2011.
Koki officially left KAT-TUN & agency on 30 September 2013. As in his message, he will still want to active in show biz and more details will be out once it settled down.
On 1 October 2014, Koki announced newly formed band, INKT which consisted 5 members. Debuted CD will be released on 8 November 2014.