Mayu Iwatani

On January 4, 2020, Mayu along with Giulia, Hana Kimura and Arisa Hoshiki made their debut in New Japan Pro-Wrestling at Wrestle Kingdom 14 in Tokyo Dome in a special STARDOM tag team exhibition match.

On December 15, Iwatani made her debut for American promotion Ring of Honor (ROH), when she was announced as part of a tournament to crown the inaugural Women of Honor Champion. At Bound By Honor, Iwatani challenged champion Kelly Klein to a title match, in which she defeated Klein for the title. Iwatani successfully defended the title twice before losing the title back to Klein at the G1 Supercard on April 6, 2019.

On November 11, both Thunder Rock and Threedom were dissolved, when Shirai turned on Iwatani, after the two had lost to Hojo and Yoko Bito in the finals of the 2016 Goddesses of Stardom Tag League. This led to Iwatani unsuccessfully challenging Shirai for the World of Stardom Championship at Stardom's year-end show on December 22. The following day, the match was named Stardom's 2016 Match of the Year. Reportedly, Iwatani was originally scheduled to win the match and the World of Stardom Championship, but the result was changed after she told Stardom that she wanted to retire from professional wrestling in 2017. After nine successful title defenses, Iwatani lost the High Speed Championship to Kris Wolf in a three-way match, also involving Kagetsu, on February 23, 2017. On April 30, Iwatani made it to the finals of her third Cinderella Tournament in a row, but was this time defeated by Toni Storm. With Storm going after the World of Stardom Championship, Iwatani chose to challenge for the Wonder of Stardom Championship. On May 14, Iwatani defeated Kairi Hojo to win the Wonder of Stardom Championship for the second time. Shortly afterwards it was reported that Iwatani was no longer considering retirement and was being positioned as Stardom's top star in the wake of Io Shirai and Kairi Hojo's departures from the promotion.

On April 23, 2015, Iwatani won the first annual Cinderella Tournament, defeating Koguma in the finals. As a result, Iwatani was granted a shot at Stardom's top title, the World of Stardom Championship, but was defeated by the defending champion, Kairi Hojo, on May 17. On May 6, Iwatani and Io Shirai, Thunder Rock, defeated Chelsea and Kairi Hojo to win the vacant Goddess of Stardom Championship. On October 11, Iwatani defeated Rosa Negra to also win the High Speed Championship. During their tag team title reign, Thunder Rock also won the 2015 Goddesses of Stardom Tag Tournament. On February 28, 2016, Iwatani became a triple champion, when she, Shirai and Kairi Hojo, billed together as "Threedom" (a combination of the words "Three" and "Stardom"), defeated Evie, Hiroyo Matsumoto and Kellie Skater for the Artist of Stardom Championship. In April, Iwatani, along with Hojo and Shirai, traveled to the United States to take part in events held by Lucha Underground and Vendetta Pro Wrestling. On April 29, Iwatani won her second Cinderella Tournament in a row, defeating Hiroyo Matsumoto in the finals. As a result, Iwatani received another shot at the World of Stardom Championship, but was defeated by Io Shirai on May 15. After setting records for both the longest reign and most successful title defenses, Iwatani and Shirai lost the Goddess of Stardom Championship to Kagetsu and Kyoko Kimura in their 11th title defense on June 16. On October 2, Threedom lost the Artist of Stardom Championship to Hana Kimura, Kagetsu and Kyoko Kimura in their third defense.

Following Hoshiki's retirement from professional wrestling in June 2012, Iwatani began teaming with Io Shirai under the team name "Thunder Rock". She also became part of a stable named Tawashis with Hiroyo Matsumoto and Miho Wakizawa. The three went on to win the Artist of Stardom Championship on December 29, 2013, by defeating Alpha Female, The Female Predator "Amazon" and Kyoko Kimura. On July 27, 2014, Iwatani won her first singles title, when she defeated her teammate Miho Wakizawa for the vacant Wonder of Stardom Championship. After a record-setting eight-month reign, Tawashis lost the Artist of Stardom Championship to Hatsuhinode Kamen, Kaori Yoneyama and Tsubasa Kuragaki on August 10, 2014. On January 18, 2015, Iwatani lost the Wonder of Stardom Championship to Act Yasukawa.

Iwatani was part of Stardom's first class of trainees. She made her professional wrestling debut at the promotion's inaugural event on January 23, 2011, facing fellow debutante Arisa Hoshiki. Afterwards, Iwatani and Hoshiki formed a tag team named AMA, which became one of Stardom's most popular acts. Despite her popularity, Iwatani was the last of the class one trainees to obtain a win in a professional wrestling ring. In June, she was defeated by Eri Susa, the other winless Stardom trainee, and subsequently became known as Stardom's weakest wrestler. Iwatani was winless for the first eleven months of her career, before finally defeating Susa in a rematch on December 25, 2011. Afterwards, Iwatani and Hoshiki became part of Io Shirai's "Planet" stable, along with Natsumi Showzuki.

Iwatani grew up on the countryside of Mine, Yamaguchi with her family, which includes two older brothers. In primary school, she practiced judo and high jump, but in high school, she began isolating herself from society, spending three years mostly indoors. After quitting high school, she fell in love with professional wrestling after seeing a Dragon Gate event. She contacted Fuka, the general manager of the World Wonder Ring Stardom promotion, who were looking for new wrestlers, and eventually moved to Tokyo in 2010 to pursue a career in professional wrestling.

Mayu Iwatani (岩谷 麻由 , Iwatani Mayu, ring name: 岩谷 麻優) (born February 19, 1993) is a Japanese professional wrestler currently signed to the World Wonder Ring Stardom promotion. Since making her debut in January 2011, she became a two-time World of Stardom Champion, two-time Wonder of Stardom Champion, one-time High Speed Champion, one-time Goddess of Stardom Champion, and a four-time Artist of Stardom Champion, while also having won the Cinderella Tournament back to back in 2015 and 2016, and the 2018 5*Grand Prix. She also makes appearances for Stardom's American partner Ring of Honor (ROH), where she is a former one-time Women of Honor World Champion. Dave Meltzer of the Wrestling Observer Newsletter has called Iwatani and fellow Japanese workers Io Shirai and Kairi Hojo "three of the best wrestlers in the world".

On June 21, Iwatani defeated Shirai to win the World of Stardom Championship for the first time in her fifth challenge, becoming the first wrestler to simultaneously hold the World and Wonder of Stardom Championships. Afterwards, Iwatani started defending both the World and Wonder of Stardom Championships in separate title matches. On September 23, Iwatani lost the Wonder of Stardom Championship to Yoko Bito in her third defense. The following day, Iwatani lost the World of Stardom Championship to Toni Storm, again in her third defense. The title change was unplanned as the match had to be stopped after only two minutes due to Iwatani legitimately dislocating her elbow, forcing referee Daichi Murayama to award the title to Storm. Iwatani returned to the ring on December 10 to take part in Yoko Bito's final match in Shin-Kiba 1st Ring.