Tomoyuki Oka

On June 30th, 2018, Oka debuted a new look and ring name, Great-O-Kharn (グレート-O-カーン , Gurēto-ō-kān) . He defeated Shota Umino with a new finisher, a Mongolian chop delivered from the second turnbuckle. Great O-Kharn started his excursion in the United Kingdom with New Japan affiliate Revolution Pro Wrestling and has started with 3 impressive wins and has since reinvented his finisher into a Crossbow submission. At Revolution Pro Wrestling's Summer Sizzler O-Kharn defeated American Superstar Shane Strickland and continued his winning streak into the Rev Pro tapings. On October 13th, 2019, The Great O-Kharn teamed with Rampage Brown to win the RPW Tag Titles. A month later, on November 24th, O-Kharn and Brown unified the RPW Tag Titles with the SWE Tag Titles when they defeated The Moonlight Express

Oka began training with New Japan Pro Wrestling (NJPW) in 2015, and made his in-ring debut on February 25, 2016, wrestling fellow rookie Katsuya Kitamura to a draw in a dark match at Lion's Gate Project 1. Oka and Kitamura wrestled to another draw in a dark match on September 1 at Lion's Gate Project 3. Oka made his televised debut on January 3, 2017, losing to his trainer Yuji Nagata. Oka once again lost to Nagata on January 27, January 31, and February 2. On February 9, Oka, Yoshitatsu and Henare were defeated by Nagata, Hirai Kawato and Jyushin Thunder Liger. Oka's first victory came on February 21, when he defeated Henare via referee stoppage after Henare suffered an ankle injury during their match. On April 13 at Lion's Gate Project 4, he teamed with his trainer Yuji Nagata to defeat Katsuya Kitamura and Manabu Nakanishi. On July 22, he and Nagata defeated Kitamura and Hiroshi Tanahashi. Oka then formed a tag team named "Monster Rage" with Kitamura. From October 12 to December 21, Oka took part in the 2017 Young Lion Cup, where he finished third with a record of three wins and two losses. Oka and Kitamura made their debuts in All Japan Pro Wrestling (AJPW) on July 5, 2017, losing to Wild Burning (Jun Akiyama and Takao Omori).

Oka excelled in amateur wrestling while in school, winning the All Japan Wrestling Championship in the 120 kg Freestyle class in 2012. Oka met Takaaki Kidani, president of Bushiroad in 2013, and was signed to New Japan Pro Wrestling (NJPW) shortly after, but didn't begin training until 2015 as he was still in university at the time. Oka is an avid anime fan, citing Milky Holmes as his favourite anime. In the past, Oka has also competed in judo, karate, sambo, kickboxing, pankration, jiu-jitsu and mixed-martial arts.

Tomoyuki Oka (岡 倫之 , Oka Tomoyuki, born June 12, 1991 in Maebashi, Gunma, Japan) is a Japanese professional wrestler trained by and signed to New Japan Pro Wrestling (NJPW).