Koji Iwamoto

In 2012 Iwamoto began training with Shinya Ishida at the Sportiva Entertainment promotion. The two made their debuts together and became rivals throughout the coming years.

In 2013, Iwamoto primarily competed in Pro Wrestling HEAT UP and Dramatic Dream Team more specifically Hard Hit DDT's brand as well as other promotions from time to time along. On February 28 Iwamoto competed in his first professional wrestling tournament at Hard Hit at the Second Grappling Tournament where he lost at the semifinals to Atsushi Aoki. On March 15, 2014, Iwamoto received his first ever title shot in a three-Way match between him, Hiroshi Fukuda and PSYCHO for the World Nice Guy Championship where PSYCHO came out victorious. On August 23 Iwamoto competed at the Next Contenders One Day Tournament defeating Kenta Hattori at the finals.

On March 22, 2015, Iwamoto participated at the Powerful Tag Tournament with Daisuke Kanehira where the duo was eliminated at the semifinals to Amigo Suzuki and Kazuhiro Tamura.

In January 2016 at Pro-Wrestling Basara, Iwamoto formed a stable name Kibatai with Ryota Nakatsu and Ryuichi Sekine. On February 6, 2016, at Heat-Up Iwamoto participated at the 2016 Powerful Tag Tournament this time with Minoru Tanaka where the two lost at the first round with Kazuhiro Tamura and Mineo Fujita. On June 16 Iwamoto defeated Daisuke Kanehira to become the #1 Contendership to the Heat-Up Universal Championship. On July 19 to August 16 Iwamoto participated in a tournament to crown the vacant GWC Six-man Tag Team Championship. His partners were Daisuke and Joji Otani; they lost at the finals to Amigo Suzuki, Masao Orihara and Ryan Upin. On August 31, Iwamoto unsuccessfully challenged Tamura for the Heat-Up Universal Championship. On October 5 at Basara Iwamoto and his friend Fuminori Abe participated at the Iron Fist Tag Tournament but lost to FUMA and Yusuke Kubo at the first round.

On 2016 Iwamoto started to compete in All Japan Pro Wrestling. In November Iwamoto took part in the 2016 Jr. Tag Battle of Glory with Fuminori Abe. They finished the tournament with only two points defeating Axe Bombers (Daichi Kazato and Kazuhiro Tamura) on the last day of the tournament. On December 26, 2016, he was signed to All Japan Pro Wrestling. In January 2017 it was announced that Iwamoto was going to participate in the 2017 Jr. Battle of Glory which he won on February 26 defeating Hikaru Sato at the finals; with this Iwamoto won the tournament in his first appearance. On March 12, Iwamoto unsuccessfully challenged Keisuke Ishii for the World Junior Heavyweight Championship. He received another shot at the title on June 28, but was this time defeated by Hikaru Sato. On July 15, 2018, he unsuccessfully challenged Atsushi Aoki for the championship, but rebounded on August 25 when he and Tajiri defeated Aoki and Hikaru Sato to win the 2018 Jr. Tag Battle Of Glory. Then the following day, he defeated Aoki to finally become the World Junior Heavyweight Champion. However, he wouldn't make any successful defenses as he lost the title to Shuji Kondo on September 22, ending his reign after less than a month. He faced Kondo again on November 29 and managed to defeat him to regain the World Junior Heavyweight Championship.