is a Japanese actor, politician, and semi-retired professional wrestler. He is best known for his work in Frontier Martial-Arts Wrestling (FMW) and is credited with introducing the deathmatch style of professional wrestling to Japan. He is a former 7-time FMW Brass Knuckles Heavyweight Champion and 3-time All Asia Tag Team Champion alongside partners Masanobu Fuchi, Yoshitatsu, and Toy Kojima.

Onita founded FMW in 1989, defeating martial artist Masashi Aoyagi under his own martial arts rules in the main event of the second night of the promotion's inaugural event. FMW later emerged as a full-fledged touring organization, moving away from martial arts-inspired shoot style matches and moving toward the rasslin'-inspired deathmatch style – which became popular with Japanese fans. He was the promotion's top star, wrestling in main event matches at sold-out events, making FMW a financially successful company, particularly for a Japanese independent promotion. Onita sold FMW to Shoichi Arai and retired from wrestling in 1995 to pursue an acting career, which was unsuccessful, forcing him to return as a wrestler in 1996. After returning to FMW, he led stables ZEN and Team Zero but departed the company in 1998 after disagreements over his position in the company.

He held the FMW Brass Knuckles Heavyweight Championship a record seven times and headlined the first six editions of FMW's premier Anniversary Show event from 1989 to 1995.

Professional wrestling career All Japan Pro Wrestling (1974–1985) Onita was the first true graduate of the All Japan Pro Wrestling (AJPW) dojo (Jumbo Tsuruta had debuted first, but he had trained in Amarillo, Texas, with Dory Funk Jr. and Terry Funk), debuting on April 14, 1974. In his early days he teamed with dojo classmate Masanobu Fuchi, who debuted only a few weeks after him. He was known as a loyal ring attendant to AJPW promoter Giant Baba, who had accepted him into the dojo despite not having graduated from high school. In the late 1970s and the early 1980s, he and Fuchi toured Memphis, Tennessee, winning the AWA Southern Tag Team titles three times.

When the junior heavyweight wrestling boom started in Japan, originally in New Japan Pro-Wrestling (NJPW) under Tatsumi Fujinami and the original Tiger Mask, Satoru Sayama, Onita was picked as the ace of AJPW's makeshift junior heavyweight division. Baba was able to get Chavo Guerrero, who had been an early rival of Fujinami, to jump over to AJPW's side, and Guerrero brought the NWA International Junior Heavyweight Championship with him, effectively establishing it as AJPW's junior heavyweight cornerstone. Onita and Guerrero's subsequent feud over the title spanned three promotions (AJPW, Jim Crockett Promotions, and Empresa Mexicana de Lucha Libre), and, while not as spectacular as NJPW's junior heavyweight division, provided a solid alternative to heavyweight-style wrestling for AJPW fans.

Onita took a hiatus from wrestling due to injury in April 1983. He attempted a comeback in May 1984. His last match prior to his retirement occurred on December 2, 1984, against Mighty Inoue. He would be replaced by his former tag team partner Masanobu Fuchi as the new junior heavyweight ace of AJPW. On January 3, 1985, Onita retired for the first time due to accumulated injuries.

Pioneer Senshi (1988) After over three years recuperating from his injuries, Onita returned to the ring in December 1988 for Pioneer Senshi, an independent promotion, losing a martial arts–inspired bout to Ryuma Go.

Frontier Martial-Arts Wrestling (1989–1998) Brass Knuckles Heavyweight Champion (1989–1993) Following his return to the ring, Onita issued a challenge to the wrestlers of the shoot style promotion Universal Wrestling Federation (UWF) but his challenge was rejected and he responded by taking on martial artist Masashi Aoyagi in a (worked) martial arts fight for the World Karate Association (WKA) on July 2, 1989, during which Onita was disqualified for using wrestling moves on Aoyagi. In the aftermath of his fight for the WKA, Onita personally promoted two wrestling shows under the Frontier Martial-Arts Wrestling (FMW) banner titled Grudge in Nagoya and Grudge in Tokyo in October and headlined both shows against Aoyagi. He lost to Aoyagi at Grudge in Nagoya and defeated him at Grudge in Tokyo. Onita shortly after developed FMW into a full-time promotion, originally basing it around shoot style matches before transitioning the company into being Japan's first death match promotion – taking inspiration from the style of matches he had seen during his earlier stay in Memphis. Even as the deathmatch wrestling style become the main trademark of FMW, the promotion would continue to hold shoot style matches. Onita would bring in numerous karate and martial arts fighters to be part of the FMW roster in the early years of the promotion.

The first street fight of FMW took place on December 4, in which Onita and Dick Murdoch defeated Jos LeDuc and Masanobu Kurisu. Onita was featured as the company's main star and the top fan favorite and headlined every show. His first Barbed Wire Deathmatch took place at Battle Creation as he teamed with Tarzan Goto to defeat Jerry Blayman and Mitsuhiro Matsunaga. After being eliminated by his frequent ally Tarzan Goto from the Battle Resistance tournament, Onita defeated Beast the Barbarian to win the WWA World Brass Knuckles Heavyweight Championship for the first time on January 17, 1990.

Onita's first feud began in the summer of 1990 when Onita defeated Lee Gak-soo in a different style fight on May 19 and then the two showed respect to each other and teamed to defeat Mitsuteru Tokuda and Sambo Asako in a tag team match on June 2. Goto was irate at Onita for teaming with karate fighters and toning down professional wrestling and he brought in Mr. Pogo to FMW and Onita began feuding with Goto and Pogo. Onita defeated Goto in an empty arena match on June 24 and then successfully defended the Brass Knuckles Heavyweight Championship against Goto in the first-ever no ropes exploding barbed wire deathmatch at Summer Spectacular. After the match, Onita and Goto ended their feud by embracing each other and putting away their differences and then Onita began a legendary rivalry against Mr. Pogo, with Onita defeating Pogo in the first singles encounter in a street fight on August 25. Onita successfully defended the Brass Knuckles Heavyweight Championship against Pogo in a Texas Deathmatch at 1st Anniversary Show.

Onita lost the Brass Knuckles Heavyweight Championship to Grigory Verichev on February 27, 1991. Onita unsuccessfully challenged Verichev for the title in a rematch on May 5 and then received another title shot on May 29, where Onita defeated Verichev to regain the renamed World Martial Arts Heavyweight Championship. On August 17, Onita defeated Jimmy Backlund, Ricky Fuji and Sambo Asako to win the Barbed Wire Deathmatch Tournament. During this time, Mr. Pogo left FMW and Tarzan Goto turned on Onita once again to renew their feud and became Onita's arch rival. Onita defeated Goto in the first-ever no rope exploding barbed wire steel cage deathmatch at the very successful 2nd Anniversary Show on September 23 at the Kawasaki Stadium in Kawasaki, which would become the venue for FMW's major events in future.

Onita and Goto reunited once again and they participated in the World's Strongest Tag Team Tournament, which they won by defeating Grigory Verichev and Koba Krutanize in the final on December 9 to win the inaugural WWA World Martial Arts Tag Team Championship. FMW phased away the martial arts style and emphasized on the deathmatch wrestling as its key feature during this time. Onita lost his World Martial Arts Heavyweight Championship to Big Titan on January 15, 1992. Onita and Goto lost the World Martial Arts Tag Team Championship to Sabu and Horace Boulder in a no ropes barbed wire street fight deathmatch on May 7. Onita regained the World Martial Arts Heavyweight Championship by defeating former boxing champion Leon Spinks in a cage match on May 24, which earned a rapid rise in popularity and stardom to Onita for having beaten a famous celebrity. A month later, Onita lost the title to The Sheik on June 25 because of an injury sustained from an attack by Tiger Jeet Singh before the match. Sheik would later reward the title to Singh. Onita lost to Singh in a jungle deathmatch on June 30, before defeating him in a no ropes exploding barbed wire deathmatch to win his fourth World Martial Arts Heavyweight Championship at the 3rd Anniversary Show.

Onita continued his success by winning the Street Fight Tournament with former rival Grigory Verichev on December 7. He ended his feud with The Sheik by defeating him for the United States Championship on January 18, 1993; Onita later returned the belt to Sheik saying that Sheik deserved the title for holding it for over a decade. This earned him Sheik's respect and both men ended their feud and became allies. Onita's success streak continued as he defeated Terry Funk in the first-ever no ropes exploding barbed wire time bomb deathmatch at the 4th Anniversary Show on May 5. Onita renewed his rivalry with Mr. Pogo, who returned to FMW in the summer of 1993 and the World Martial Arts Heavyweight Championship was replaced with the FMW Brass Knuckles Heavyweight Championship. Onita defeated Pogo in a no ropes exploding barbed wire time bomb deathmatch to win the vacant Brass Knuckles Heavyweight Championship at the Summer Spectacular show on August 22. Onita successfully defended the title against W*ING's former ace Mitsuhiro Matsunaga in a no ropes exploding barbed wire deathmatch at Year End Spectacular, and then the two men became allies to feud with Mr. Pogo and his entourage.

Second retirement (1994–1995) On January 6, 1994, Onita lost the Brass Knuckles Heavyweight Championship to Mr. Pogo in a street fight. After losing the title, Onita began his next feud with Genichiro Tenryu after the team of Onita and Tarzan Goto defeated Tenryu and Ashura Hara at Wrestling and Romance's Revolution Rumble when Onita pinned Tenryu. Onita and Tenryu competed in a no ropes exploding barbed wire deathmatch at 5th Anniversary Show on May 5, which stipulated that if Onita lost, he must retire from professional wrestling. Tenryu defeated Onita to even the scores and then Onita debuted his "Mr. Liar" character by saying that he was not going to retire immediately and that the retirement stipulation would take place a year later. Onita began his retirement tour which would conclude at the following year's 6th Anniversary Show. Onita reunited with Tenryu as the two teamed with Crusher Bam Bam Bigelow at WAR's 2nd Anniversary Show and the trio won a Six-Man Tag Team Tournament.

On July 31, Onita teamed with Mitsuhiro Matsunaga to defeat Mr. Pogo and Hisakatsu Oya to win the Brass Knuckles Tag Team Championship. Around the same time, Onita renewed his feud with Masashi Aoyagi, who had returned to FMW and attacked Onita after a match. Their rivalry culminated in a no ropes electrified explosive barbed wire barricade double hell match at Summer Spectacular, which Onita won. Onita defeated Mr. Pogo to win his sixth Brass Knuckles Heavyweight Championship on September 7. After the match, former W*ING wrestler Yukihiro Kanemura made his FMW debut and attacked Onita to avenge the demise of W*ING. Mitsuhiro Matsunaga visited Kanemura at hospital as Kanemura was getting treated for some burns which he had suffered during a past match. Onita accused Matsunaga of turning on FMW and mistrusting his loyalty and this angered Matsunaga, who then joined Kanemura and Mr. Pogo to form W*ING Alliance and Onita feuded with the group for the rest of his retirement tour. As a result, Onita and Matsunaga broke up as a team and vacated the Brass Knuckles Tag Team Championship in October.