After training in the NOAH dojo under the watch of Naomichi Marufuji, Daisuke Harada and Atsushi Kotoge, Kumano made his in-ring debut in January 2013, losing in a battle royal. In doing so, Kumano became the first wrestler to make his debut in NOAH since Shuhei Taniguchi in 2005. Kumano's next 7 matches were all battle royals, and he lost all of them. His singles debut took place on February 9, when he lost to his trainer, Kotoge. On May 11 at Kenta Kobashi's retirement show, Final Burning in Budokan, Kumano wrestled the biggest match in his career up until that point, losing to veteran Masanobu Fuchi. Kumano remained winless until June 30, when he, Harada and Taiji Ishimori defeated Kaiser, Pesadilla and Super Crazy. The following month, Kumano entered the NTV G Cup Junior Heavyweight League, finishing last in Block A with zero wins and zero points. On August 24, Kumano achieved the biggest win of his career so far, when he and Harada defeated his trainer Kotoge and Ishimori. Kumano received his first opportunity at a championship on September 16 when he and Harada unsuccessfully challenged Jushin Thunder Liger and Tiger Mask IV for the GHC Junior Heavyweight Tag Team Championship. In July 2014, Kumano once again entered the NTV Junior Tag League, this time with Diamond Ring's Mitsuhiro Kitamiya. The duo won their first match, defeating Jinzo and Rocky Lobo, but lost every other match they were involved in, finishing last in Block B with 1 win and 2 points. Throughout 2014 and 2015, Kumano remained at the lower end of most cards and lost the majority of his matches, commonplace for young Japanese wrestlers as a way of learning respect and earning your opportunities. On June 13, 2015, the 6 year anniversary of NOAH founder Mitsuharu Misawa's death, Kumano once again unsuccessfully challenged for the GHC Junior Heavyweight Tag Team Championship, teaming with Genba Hirayanagi in a loss to Suzuki-gun (Taka Michinoku and El Desperado). In July, Kumano took part in the Global Junior Heavyweight League, finishing last in Block A with zero wins and zero points. In September, Kumano entered the NTV G Cup Junior Heavyweight Tournament for a third time, teaming with Super Crazy and winning only one match, leaving them with two points and unable to advance to the final.
