Kawahira, along with Sepira, belongs to a special species that had existed on Earth even before the humans whose duty is to protect the planet with Tri-ni-sette. Arcobaleno Pacifiers were first created from the seven stones when only five of his people himself and Sepira included remained. When he and Sepira were the only two remaining members and unable to provide the Tri-ni-sette with their own powers, they decided to split the Tri-ni-sette into another two sets of seven stones: Vongola Rings and Mare Rings. Arcobaleno Pacifiers and Vongola Rings were given to the humans and Mare Rings kept by Sepira and her Famiglia. At some point, Sepira and Kawahira parted ways due to different opinions; while Sepira wanted to coexist with humans, Kawahira didn't. Since then, Kawahira, as Checker Face, continued his duty to monitor the entire Tri-ni-sette and showed himself only to select the successors of Arcobaleno pacifiers.
Through generations, he brought the Arcobaleno together, gathering them as the I Prescelti Sette, which is translated to "World's Strongest Selective Seven" in the series. In Italian, it translates to the "the chosen seven" or "the selected seven." His gathering of the seven resulted in the gathered people becoming Arcobaleno and being cursed with their baby bodies. When he was first shown meeting with Reborn, he was holding a Clear Arcobaleno Pacifier, the pacifier of the Flame of Night that Bermuda von Veckenschtein held when Jaeger sealed the deal between Giotto and Simon Cozzato (the Vongola and Simon Primo, respectively) for their descendants to not fight each other.
While the Vongola are on the run from the Millefiore with Uni, Kawahira tells them to get inside and that he would take care of the Six Funeral Wreaths. He then uses illusions from his Hell Ring to make it look like the street is crowded, though Zakuro stops in front of his shop and searches for the group.
When he is threatened to be burned along with his shop, Kawahira uses his illusions to have Zakuro chase after an invisible "murderous intent." Unfortunately Byakuran comes back from one of the parallel worlds and states that he has found where Kawahira and the Vongola are hiding and sends his Six Funeral Wreaths after them. Although Kawahira has helped them out, he quickly leaves claiming that he has a trip to go to, but not before a suspicious Reborn starts questioning who he is. Kawahira merely shrugs it off and leaves before Reborn could ask him more questions. Reborn still thinks that Kawahira is suspicious and states that he doesn't like him somehow.
Checker Face was first shown in Reborn's dream, which seemed as a recollection of the past, his gathering of the "I Prescelti Sette"; however, when they gathered in the dream, they suddenly reverted to their cursed forms, Colonnello replacing Lal Mirch and Luce disappearing. He then revealed himself and asked if the Arcobaleno (sans Aria) if they wanted to solve the "Curse of the Rainbow". The Arcobaleno immediately answered with a "yes", except for Reborn. He explains the rules of a fight to determine the strongest Arcobaleno; however, Reborn argues with him for a while, Checker Face preparing to leave as a result, but Reborn then agrees to the fight. As a result of gathering the Arcobaleno in his dream, all the Arcobaleno asked various people for a favor, which was to fight for them. Colonnello requested CEDEF's head, Iemitsu's help. Viper requested Varia's boss, Xanxus's help. Fon was represented by Kyoya Hibari, on the condition that he was to be the only representative. Skull approached Enma Kozato by feeding two cats that Enma usually feeds, and demanded his help in return. Reborn requested Tsuna and Dino's help, as they were his students. Verde went to Kokuyo Land and demanded Mukuro Rokudo's assistance. Aria, the Sky Arcobaleno, gives up her right to have her short-lifespan Arcobaleno curse to be removed and instead gives it to her daughter from ten years later, Uni, who enlists Byakuran, the Six Funeral Wreaths, Gamma, Nosaru, and Tazaru's help. 4 days before the fight starts, Wonomichi, Checker Face's messenger, goes to each of the representatives and explains the rules of the battle.
At the end of the first day of the Representative Battle, Checker Face announces the battle rankings thus far through the Rainbow Wristwatches.
At the end of the second day of the Representative Battle, Checker Face announces the battle rankings through the Rainbow Wristwatches and formally introduces Team Bermuda and inducts them into the Representative Battle of the Rainbow.
At the end of the last battle, Checker Face shows up to announce the winner of the Representative Battle and, to everyone's surprise, he reveals his true identity to be Kawahira, the frequent customer to future I-Pin's noodle shop. He then proceeds to reveal this history behind the Tri-ni-sette, demonstrates the power of his Dying Will Flames, and reveals that he and Uni were the only members of their species left. He then prepares to undergo the Arcobaleno change process, but Talbot suddenly intrudes and introduces an object that could supposedly get rid of the necessity of Arcobaleno. Kawahira at first hesitated, but after Uni convinced that she can see the bright future of the Tri-ni-sette, he immediately agrees as he actually feels that if there's another way without sacrifising anybody, he would like to entrust the Tri-ni-sette to the future generations. He and the others gathered around the jars and filled it with their flames at the fullest and then removed the Arcobaleno Curse. Afterwards, Kawahira's whereabouts is unknown.