KAWAHIRA

A man who lives in the future at a real estate firm that belonged to an old lady Haru knew in the past. He is constantly referred to in earlier episodes as a frequent customer of Adult I-Pin's ramen delivery service, but makes his first appearance when Tsuna and company are trying to hide from the Six Funeral Wreaths. He possesses a ring that can create strong illusions and he also has the ability to produce and control a killing intent, in order to lure away enemies searching his place. He does not outwardly state his true motives but claims that Tsuna and his friends owe him one for his help.

HANA KUROKAWA

Hana Kurokawa (黒川 花 Kurokawa Hana) is a classmate of Tsuna and Kyoko's friend. She appears more observant and thoughtful than most of the other characters. Though she does not know the truth, she remains suspicious of Tsuna's and his friends' activities, even in the future. She has a crush on the 15-year-old Lambo. At the same time she hates children (especially the child form Lambo), to the point where she gets hives when she gets annoyed by them. In the future, her adult self gives the past's Kyoko a message from the adult Ryohei.

NANA SAWADA

Nana Sawada (沢田 奈々 Sawada Nana) is Tsuna's mother, who, despite caring deeply for him, has fairly little belief in her son succeeding in life. She helps feed all the people that are presently living in her house and does not see anything strange with any of them. She seems to be unaware of the fact that both her husband and her son are part of the Mafia, but is aware they are both up to something dangerous. She is voiced by Rika Fukami in the anime.

FUUTA

Fuuta (フゥ太 Fūuta) is a young boy who ranks people by their abilities in a book half his own height. He has an extremely wide range of knowledge on thousands of people and is considered to be a valuable informant for the Mafia, sometimes being paid insane amounts of money for a copy of certain rankings, but due to this, he is often chased by the Mafia. When he ranks people, gravity around him becomes distorted, making objects around him float, and images of stars and galaxies appear in his eyes. It is unknown how he actually gathers his information, some rumours say he talks to a ranking star, and his rankings do become skewed when it rains.He also has to be looking at the person to determine their rankings. He calls Tsuna his big brother referring to Tsuna as Tsuna-ni, and starts living in his house.

In the future, after gathering information with Bianchi, Fuuta, who now carries a suitcase rather than a book, returns to Japan with crucial information about the Millefiore Family. Fuuta also reveals that he was Lambo's guardian until three years before Tsuna's arrival in the future, and prefers that Lambo not be endangered.

I-PIN

I-Pin (イーピン Īpin) is a 5-year-old assassin from Hong Kong. She is regularly transformed into her 15-year-old self by way of Lambo's Ten-Year Bazooka. The 15-year-old "Adult I-Pin" is now fluent in Japanese, and despite the fact that she is one of the most promising young assassins, she works part-time at a Chinese Restaurant ten years later in order to earn money for college tuition, though she still retains her skills. I-Pin's main ability is the usage of Gyoza-Ken, which combines her martial arts abilities with special gyoza buns laced with the scent of garlic, the latter of which numbs the brain and forces the muscles to involuntarily move on their own. Her most destructive ability is the "Pinzu-Time Bomb", activated whenever I-Pin expresses extreme shyness. Pin-numbers (such as those used in mahjong) appear on her forehead, counting down until it turns her into a human bomb that can create a small crater with its destruction. Due to her near-sightedness, she sees Lambo as the broccoli monster, and often beats him up. She also has a crush on Kyoya Hibari, who bears a striking resemblance to her master, and often activates her Pinzu-Timed Super Explosion after seeing him. She is voiced by Li-Mei Chiang in the anime.

DOCTOR SHAMAL

Dr. Shamal (Dr. シャマル Dr. Shamaru) is a crazed womanizer who hits on every cute woman he sees, though often unsuccessfully. He is said to be hiding in Japan after being charged in his own country for putting the moves on 2082 women simultaneously, one of which being a queen. He is both a skilled doctor, albeit one that refuses to treat men, and a renowned assassin known as "Trident Shamal" who was even asked to join the Varia. His primary means of combat stem from the 666 pills he carries that contain trident mosquitoes, his own breed of genetically-altered mosquitoes named for their trident-shaped stingers that infect his enemies with deadly diseases. He claims to be infected with 666 diseases that have no effect on him due to the negating effects of each disease; if he has a disease that rapidly decreases body temperature, then he has another one that increases it, and so on. Shamal also happens to be the one that introduced Hayato Gokudera to bombs when he used to work for Gokudera's family. He agrees to become Gokudera's home tutor during the Vongola Tournament, but only after Gokudera learns that protecting his own life is just as important as defending those around him. He is voiced by Toshinobu Katsuya in the anime.

HARU MIURA

Haru Miura (三浦 ハル Miura Haru) is an eccentric and peppy girl who has a tendency to jump to wild conclusions, and has various odd costumes that she designs herself, as well as a myriad of wild habits. Despite this, she attends Midori Middle School, one of the toughest elite schools to get into in the area. She initially adores Reborn, but after she is saved from drowning by Tsuna, she diverted her adoration towards him instead. She loves and is overprotective of children and is usually the one to babysit Lambo and I-Pin with Kyoko.According to Tsuna, adult Haru has become more feminine, but her way of thinking is still the same. She is voiced by Hitomi Yoshida in the anime.