in 2014. On February 9, 2005, Yoshihiko made his debut in
DDT Pro-Wrestling under the gimmick of being
Muscle Sakai's younger brother. He competed in a match against Kuma Sentoin but withdrew due to a mysterious "illness" (air leakage) that caused his body to deflate. Yoshihiko continued to participate in matches throughout 2005 but did not return until 2009. At
Judgement 2009, Yoshihiko appeared as
Danshoku Dino's tag team partner. Together, they defeated
Piza Michinoku and
Antonio Honda to become the number one contenders for the
KO-D Tag Team Championship. During the match, Honda destroyed Yoshihiko's head, but the character "reincarnated" when replaced with another doll mid-match. The new version was dressed in a costume resembling
The Great Muta. At Max Bump 2009, Yoshihiko and Dino challenged
Kota Ibushi and
Kenny Omega for the titles. Yoshihiko's head burst after a giant swing from Omega, and he was carried out of the arena. Later in the match, he reappeared dressed in
The Undertaker's biker outfit and made a comedic tricycle entrance. Despite performing with visible "injuries," Yoshihiko and Dino were narrowly defeated after a 30-minute match. Following the bout, Antonio Honda and two accomplices appeared and "shot" Yoshihiko. Yoshihiko later won the
Ironman Heavymetalweight Championship from Yoshiaki Yago on June 28, 2009. At
Ryōgoku Peter Pan on August 23, he competed in a
rumble rules battle royal, losing the title to
Toru Owashi but reclaiming it later in the match as "Sumo Yoshihiko," wearing a and . On October 25, Yoshihiko challenged Ibushi, then
KO-D Openweight Champion, in a double title match at Welcome To Never Land 2009 in
Korakuen Hall, Tokyo. Performing under a parody of
Hulk Hogan, Yoshihiko showcased exaggerated power moves, including eight consecutive
Canadian Destroyers. After a 25-minute match, he was pinned by Ibushi's
Phoenix Splash. However, after interference from outside the ring, Yoshihiko managed to roll up Ibushi and regain the Ironman Heavymetalweight title. Later, his mask was removed by Dino and
Masa Takanashi, revealing "Robo Chojin." On December 31, 2009, Yoshihiko entered the 108-participant New Year's Rumble at Tenka Sanbun no Kei: Ōmisoka New Year's Eve Special. He eliminated
Yotsukaider with a
Hurricanrana before being eliminated after a double attack from
Kengo Mashimo and Hiroyuki Miyamoto. Yoshihiko's entrance reportedly received one of the loudest reactions of the event. On June 13, 2010, Yoshihiko,
Mitsuru Sato, and
Keisuke Ishii won the
UWA World Trios Championship from
Tokyo Gurentai and competed at
Ryōgoku Peter Pan 2010. They lost the titles on July 25 in a
three-way match also featuring
Kudo,
Antonio Honda, and
Yasu Urano, with
Great Kojika, Mr.#6, and
Riho emerging as the winners. On April 29, 2011, Yoshihiko made his first appearance outside DDT and Union at
Kaientai Dojo's GWSP6 event, teaming with Ibushi for a failed challenge for the
WEW Hardcore Tag Team Championship. On February 15, 2015, after Ibushi won the KO-D Openweight Championship, he named Yoshihiko as his next challenger. The match was held on March 21, 2015. Yoshihiko executed nine consecutive
Canadian Destroyers before losing to Ibushi's
Last Ride,
Phoenix Splash, and single-arm crab hold. In July 2020, Yoshihiko embarked on a solo U.S. tour and faced
Joey Janela in an Ironman Heavymetalweight Championship match at
Game Changer Wrestling's Homecoming Weekend Part 2 in
Atlantic City, New Jersey, where he was defeated. Later that year, Yoshihiko and
Mao won the BZW Tag Team Championship at the Alcatraz event in
Faches-Thumesnil, France, defeating Jack Sans-Nom and Paul Robinson via a "Rainmaker." They successfully defended the titles on January 3, 2025, at New Year☆Dramatic Parade 2025: Answer Will Be Given in a Year. Yoshihiko made a return at Fighting Beer Garden 2025 in Shinjuku on September 9, 2025, parodying
The Undertaker's entrance to challenge
Kazuki Hirata for the KO-D Openweight Championship. A contract signing was held on September 17 at a DDT outdoor event. On September 28 at Dramatic Infinity 2025, Yoshihiko was defeated by Hirata in the main event. Following the match, a storyline twist revealed
Yuki Ueno as the mysterious figure aligned with Yoshihiko, who subsequently cashed in his challenge and won the KO-D title. On September 30, 2025, DDT announced via X (formerly Twitter) that Yoshihiko would be taking a hiatus due to accumulated "injuries," stating: "After years of accumulated damage, Yoshihiko will undergo a full overhaul and will be out for a long time." ==Championships and accomplishments==