Wrestle Kingdom 12
Behind the scenes, Jericho became part of a group of people that started pushing for the show to air on American pay-per-view (PPV) for the first time since Wrestle Kingdom 9 in 2015. Some in NJPW felt that airing the show through NJPW World would be enough, hoping that the Jericho signing would increase subscriber numbers. While NJPW was now considered more popular than in 2015, when Wrestle Kingdom 9 did 14,000 buys on American PPV, it was noted that the 2018 show would take place early Thursday morning in the United States as opposed to a weekend like it did in 2015, which was seen as a major negative in terms of getting buys from the country. In late November, it was reported that NJPW had turned down Fite TV's offer for PPV rights outside of Japan and would not be allowing the event to air on American PPV, wanting their streaming service to be the only way to see the event live. On December 3, it was announced that the top matches from the show would air on AXS TV on January 6, 2018, as part of an 11-hour block of NJPW programming with additional matches airing between January 12 and February 9. Five matches, including the top three matches, will air on TV Asahi as part of a special episode of "World Pro Wrestling" on the night of January 4.
Wrestle Kingdom 12
Wrestle Kingdom 12 featured ten professional wrestling matches that involved different wrestlers from pre-existing scripted feuds and storylines. Wrestlers portrayed villains, heroes, or less distinguishable characters in the scripted events that built tension and culminated in a wrestling match or series of matches.
Wrestle Kingdom 12 was main evented by Kazuchika Okada defending the IWGP Heavyweight Championship against Tetsuya Naito. The storyline behind the match dates back to 2013, when Naito won the G1 Climax tournament to earn a shot at Okada and the IWGP Heavyweight Championship at Wrestle Kingdom 8 on January 4, 2014. However, at that time, Naito, despite being a clean cut babyface, was disliked by NJPW fans, which led to the company changing their course of action, announcing a fan vote to determine whether the match between Okada and Naito or an IWGP Intercontinental Championship match between Shinsuke Nakamura and Hiroshi Tanahashi would main event Wrestle Kingdom 8. Nakamura and Tanahashi won the vote, resulting in Okada and Naito losing their main event spot. Okada went on to defeat Naito in the match to retain the title. In the summer of 2015, Naito traveled to Mexico to work for the Consejo Mundial de Lucha Libre (CMLL) promotion, where he joined the villainous "Los Ingobernables" stable. Upon his return to NJPW, Naito, using the NJPW fans' rejection of him as a catalyst, completely reinvented his character, eventually leading to him forming the "Los Ingobernables de Japon" stable. Despite now being a villain, fans eventually started getting behind Naito with "Los Ingobernables de Japon" merchandise becoming NJPW's top seller. When Naito defeated Okada at Invasion Attack 2016 on April 10 to win the IWGP Heavyweight Championship for the first time, he had the crowd solidly behind him. Naito eventually went on to lose the title back to Okada on June 19, 2016, at Dominion 6.19 in Osaka-jo Hall.
On August 13, 2017, Naito defeated Kenny Omega in the finals to win the 2017 G1 Climax. With Naito now being fully embraced by NJPW fans, this was seen as the conclusion of a four-year arc that started at the 2013 G1 Climax, where he was rejected by the same fans. Following the win, Naito gained possession of the Tokyo Dome IWGP Heavyweight Championship challenge rights certificate, which granted him a shot at the IWGP Heavyweight Championship at Wrestle Kingdom 12. On October 9 at King of Pro-Wrestling, Naito successfully defended the certificate against Tomohiro Ishii, while Kazuchika Okada successfully defended the IWGP Heavyweight Championship against Evil, setting up the main event of Wrestle Kingdom 12 between champion Okada and challenger Naito. The match was officially announced in a press conference the following day. As part of the build-up to the title match, Okada introduced a new submission hold, a cobra clutch, as a counter to Naito's finishing maneuver, "Destino". However, on December 18, in their final confrontation before Wrestle Kingdom 12, Naito managed to counter himself out of the hold and hit Okada with the "Destino", leaving him laid out. Okada has held the IWGP Heavyweight Championship ever since defeating Naito at Dominion 6.19 in Osaka-jo Hall, having successfully defended the title eight times, and enters the match as the longest-reigning champion in the title's history. This match would mark Okada's fourth consecutive and overall fifth Wrestle Kingdom main event, while Naito had never main evented the show before.
On November 5, 2017, at Power Struggle, Chris Jericho made a surprise return to NJPW, appearing in a video, where he challenged Kenny Omega to a match at Wrestle Kingdom 12 in Tokyo Dome. The challenge was quickly accepted by Omega, who had been engaged in a "Twitter feud" with his fellow Winnipegger over the past weeks. The match, contested for Omega's IWGP United States Heavyweight Championship, was officially announced the following day. Due to the high-profile status of the match, Omega began petitioning for Wrestle Kingdom 12 to have a "double main event" much like the Wrestle Kingdom shows had had in 2013, 2014 and 2015. Omega stated that he agreed that Okada and Naito should have the final match of the show, but felt that he and Jericho should have the second to last match, claiming that just four months after the creation of the IWGP United States Heavyweight Championship, he had already made it the number two title in NJPW over the IWGP Intercontinental Championship. Jericho made his in person return at the December 11 show, attacking and bloodying Omega following his match, while also laying out a referee, a young lion and Don Callis. At a press conference the following day, Omega stated that with the attack Jericho had turned their upcoming "gentleman's contest" into a fight, before attacking his Wrestle Kingdom 12 opponent. During the same conference, NJPW officially announced that Wrestle Kingdom 12 would feature a double main event with the IWGP Heavyweight and United States Heavyweight Championship matches. Naito stated that he was disappointed with the decision, adding that NJPW would never become the number one promotion in the world as long as they were humoring WWE. On December 18, NJPW announced that, as a result of both Omega and Jericho demanding it, the match had been turned into a no disqualification match.