The Kokuyo Junior High Gang, or simply Kokuyo, is a group led by Mukuro Rokudo, created after he broke out of prison. The majority of the group consists of the people who escaped from the prison with Mukuro.
Following multiple massacres of mafia famiglias, Lancia under the name of 'Mukuro Rokudo' was arrested and imprisoned with Chikusa Kakimoto and Ken Joshima. The real Mukuro Rokudo broke them out along with M.M, Birds, and the Bloody Twins.
With all the escapees, Mukuro established the gang in order to find the Vongola Decimo to execute his plan of engulfing the world with darkness, disaster, and war. In order for his plan to work, he needed experience. So, Mukuro planned to destroy something smaller than the world first, the Mafia, who he blamed for the experimentation and torture he underwent in his own famiglia. He planned to take control of the Decimo and use the Vongola's power to enact his plan. The idea also applied to his plan of destroying the world, taking control of the world's greatest leaders, and starting a World War.
The gang's plan is foiled when Tsunayoshi Sawada enters Hyper Dying Will Mode for the first time and wins the duel against Mukuro. After all the chaos they caused in Namimori, at least Chikusa, Ken, and Mukuro are arrested by the Vindice.
Ken and Chikusa escape with Mukuro's help, who willingly becomes a distraction to bait the Vindice officers. It was effective, especially since Mukuro was their primary target for being the main culprit. Mukuro is sent back to Vindice Prison and put into their lowest and strictest level.
Ken and Chikusa return to Kokuyo Land with orders to find Mukuro and protect Chrome Dokuro. Chrome became Mukuro's primary medium and connection with the outside world, and the two of them are interchangeably considered Tsuna's Guardian of Mist.
After the battle with Demon Spade, the Vindice acknowledged Mukuro's efforts and release him from Vindice Prison. As a result, Mukuro immediately breaks ties with Tsuna and even declares "war" on Tsuna, resolving to defeat him in the Representative Battle of the Rainbow as Verde's representative. He also kicked Chrome out of the gang and leaves her in Tsuna's care. Intending her to become independent and build an identity for herself now that he no longer needed to share her body.
While Lancia had left to seek redemption in Europe, neither Birds and the Bloody Twins reappeared, however, M.M. willingly joined back with the gang. With Chrome's exclusion and the addition of Fran, the gang became Team Verde.
Kokuyo Junior High Gang
- Chrome and Fran are the only members of the gang who don't participate in the battle with Tsuna and his Guardians during the Kokuyo Arc and had no connection with the Mafia prior to becoming part of the gang.
- In the cover of chapter 271, Future Fran was included comically lying on the ground and wore the Kokuyo uniform, implying that Future Fran was still part of the gang even though he has joined Varia, as he was Mukuro's disciple then. This is further hinted on the manga cover, as it states that "they [the Kokuyo Gang] have come together once more... With newcomers!"
- Despite now living separately from the gang and never included with the gang in the Character Introduction from volume 36 onwards, Chrome is still considered as a member of Kokuyo Gang, proven in the team's introduction in chapter 354 and also in every manga volumes extra (excluding volume 37-39), Pineapple Tsushin, that exclusively for Kokuyo members only. The recent extra from Akira Amano's twitter also revealed that Chrome is still receiving allowance from the gang.
- M.M once stated that Mukuro's payment is the best and even stated that Varia's payment is cheaper, implying that Kokuyo Gang have lots of money. Strangely, during Chrome's stay in Kokuyo Land, they only buy snacks to eat and in Drama CD, their monthly allowance is only 500 Yen that it even took Ken three days to decide what food he should bought because they're very careful to spend the money. However, once Mukuro returned, they once again have more money to spend. This may mean that Mukuro is the one who controls the flow of money for the gang.
- In Everyone's Ordinary Daily Life, it's revealed that once a month Kokuyo Gang is holding an ōsoji (house cleaning) by cleaning the Kokuyo Land more thoroughly than usual. All members are required to clean the entire place, except Mukuro who is only relaxing while watching them cleaning.