Despite failing the tryout, Ishikawa was invited to work for the company anyway and served as an accountant and receptionist for DDT between 2002 and 2003, while occasionally training as a wrestler.

[8] On March 27, 2011, at DDT's 14 Anniversary Show, Ishikawa won a battle royal, giving him the right to a KO-D Openweight Championship match in the future.

Ishikawa captured the KO-D Openweight Championship for a fourth time in August 2016, defeating Konosuke Takeshita at Peter Pan.

Ishikawa competed in his first ever deathmatch on January 2, 2009, teaming with Ryuji Ito to take on childhood friend Takashi Sasaki and Yuko Miyamoto.

[22] In 2016, Ishikawa won the Ikkitosen Strong Climb Tournament for a second time, defeating Daichi Hashimoto and Hideyoshi Kamitani in the semi-final and final respectively on the same night to win.

[23] Ishikawa debuted for All Japan Pro Wrestling (AJPW) in 2015, and in September of that year, took part in the Ōdō Tournament, making it to the semi-final where he was eliminated by Akebono.

[24] In December, he teamed with Hoshitango in the Real World Tag League, finishing with six points but failing to advance past the group stages.

Calling themselves "Violence Giant", the two entered the World's Strongest Tag Determination League in December, where they defeated Daichi Hashimoto and Hideyoshi Kamitani in the finals to win the tournament.

[27] They once again entered the World Tag League in December 2018, making it to the final where they lost to Dylan James and Joe Doering, however, they managed to retain the championships in the rematch.

They dropped the belts to Daisuke Sekimoto and Yuji Okabayashi at a BJW show on January 13, but regained them on March 19 in Korakuen Hall.