Team Fon vs. Team Reborn is a battle occurring between the Cloud Vongola Guardian Hibari acting as the representative of the Storm Arcobaleno Fon, and the Storm Vongola Guardian Hayato Gokudera, the Rain Vongola Guardian Takeshi Yamamoto, and the Sun Vongola Guardian Ryohei Sasagawa as representatives of the Sun Arcobaleno, Reborn, on the first day of the Representative Battle of the Rainbow.
Gokudera, Yamamoto, and Ryohei are running to the site of the explosion where Tsuna is fighting Iemitsu Sawada to investigate, but they are interrupted by Hibari with Fon sitting atop his head, accompanied by Hibird with Lichi, the latter sitting atop the former's head, and Hibari grimly states to Gokudera, Yamamoto, and Ryohei that he would bite them to death.
Hibari swings out his tonfas' double chains at the 3 other Guardians, but they duck and dodge. Ryohei calls out Kangaryuu (Version X) and enters Cambio Forma Version X. Ryohei charges, but Hibari merely swings his tonfas and destroys Ryohei's Rainbow Wristwatch, ending his eligibility in the battle royale. Gokudera question Hibari why he was attacking, but Hibari responds that Reborn's team was full of people that he wanted to bite to death. Gokudera and Yamamoto agree to team up to take on Hibari. Gokudera activates his Cambio Forma and Yamamoto brings out Kojirou. Gokudera uses his new Zero Ignite and creates a smokescreen, but Hibari brings out Roll and swings at the two with his tonfas' chains. However, it is revealed that Yamamoto had Kojirou put some Rain Flames in the smokescreen. Thanks to the Rain Flame's Tranquility characteristic, which immobilized Hibari, Gokudera and Yamamoto escape.