He competed in several signature events of the promotion such as the DDT Judgement branch, making his first appearance at Judgement 2016: DDT 19th Anniversary on March 21, where he teamed up with his "World Heaviest Heavy Metal Tag/Iron Priest" tag team partner Fuma and Sagat to defeat Takumi Tsukamoto, Daichi Kazato and Gouma Ryu.

Kubo made his first appearance at DDT BASARA Raising An Army ~Stake Everything~ on January 21, 2016, where he fell short to Hi69 as a result of a singles match.

[10] He eventually won his first title in the company, the Iron Fist Tag Team Championship alongside Fuma by defeating Sento Minzoku (Daiki Shimomura and Isami Kodaka) in the finals of a tournament to become the inaugural champions.

[13] At BASARA 207 ~ Takagari 14 on December 17, 2022, he competed in a battle royal won by Fuminori Abe and also involving Daiki Shimomura, Sagat, Trans-Am Hiroshi, Masato Kamino, Takato Nakano and many others.

[14] Kubo competed in a couple of the promotion's signature events such as the "Heaven Summit Itadaki", making his first appearance at the first-ever edition of the tournament from 2016, where he fought in the block A where he scored a total of four points after going against Isami Kodaka, Ryota Nakatsu, Sagat and Ryuichi Sekine.