Nana Sawada is a kind woman and a good mother who sometimes displays a paradoxical lack of concern for her son. She is very much in love with her husband, but, like many characters in the series, is oblivious to both Tsuna's and her husband's involvement with the Mafia. Despite the dangerous situations she and her son always seem to be embroiled in of late, she curiously is generally unfazed. Similarly, as with both her husband and her son, she seems to be accustomed to caring for and not giving up on people who others see as lazy and worthless layabouts.
Iemitsu Sawada is another story altogether. He has been absent for much of Tsuna's life and is viewed by his son as a lazy slacker and a deadbeat dad, although ultimately his character comes off as outrageous, taking ludicrous jobs and wantonly distributing alcohol. Although Tsuna thinks very lowly of him, his father seems to have great respect and high hopes for Tsuna's future, since he is the one who suggested making Tsuna the next Vongola Boss of the Vongola Famiglia. Despite his worthless appearance, Tsuna's father has also steadfastly provided for his family for years and pulls strings behind the scenes for his son, as well as being the head of CEDEF
I don't need. . . this kind of power! If you want me to inherit such mistakes then. . . I.. I WILL WIPE OUT THE VONGOLA!
Giotto is Tsuna's ancestor and the founder of the Vongola. Tsuna trusts Giotto completely and seems to hold him in high regards. He stands up for Giotto when someone questions his actions, like when Enma told Tsuna about Giotto's betrayal of Simon Cozzato. He stated quite confidently that Vongola Primo was not the kind of person who would do such a thing.
In turn, Giotto sees Tsuna as his true successor and has helped him when he seemed to be in trouble, such as in Tsuna's battle with Byakuran, where Giotto appears to unlock the true power of the Vongola Ring; something which he had not done for eight generations of Vongola Guardians, as he believes that Tsuna will understand the true meaning of the Rings and his will.
Stop joking around! Why do you think we're fighting!?! Because we're still gonna have a snowball fight and watch fireworks together! That's why we're fighting! That's why we got stronger!! So that everyone can laugh together again!! If you die, then all that no longer has any meaning, right!?!
At first, Hayato was considered a threat towards Tsuna, as he refused to accept Tsuna's status as being the tenth boss of the Vongola, and decided to test his him with the use of Dynamite, after Tsuna saved his life, Hayato became devoted to Tsuna and aimed to become his right hand man. Even after his loyalty, Tsuna still considers him to be quite scary, and is unable to refuse Hayato's request at being his right hand man because of this.
Tsuna is often flustered by Hayato's enthusiasm, but considers him to be a good friend and truly cares for him, such as him expressing his concern over the Hayato during his fight against Belphegor, as the circumstances would have killed him, convincing him to abandon the half ring, and tearing up with reunited with him.
Hayato is incredibly loyal to Tsuna, becoming hostile towards individuals who he views as hurting or discrediting towards the tenth. He is extremely enthusiastic about mafia activities, training, or becoming stronger for the "glory of the tenth" or the Vongola, which often leads to Tsuna being needlessly injured.
When first meeting Takeshi, he admired him as someone that was greatly respected by many of his classmates. When the two first became friends, Tsuna saw Takeshi as one of the last bastions of normalcy in his life, which was otherwise dominated by violence and the mafia, especially as Takeshi continues to think that the entire situation is merely a role-playing game. Unfortunate for Tsuna, as Takeshi takes the "role-playing game" very seriously, and Tsuna often finds himself unwillingly dragged along by Takeshi's seemingly misplaced calmness and confidence.
Tsuna definitely sees Takeshi as a true friend, albeit much more sensible that Hayato, and often shows a lot more trust towards Takeshi due to his kindness, not worry about his as much as his other friends. Tsuna is shown to truly care about Takeshi especially when injured during the Inheritance Ceramony, where he falls into a state of depression after his friend is hospitalized.
Takeshi, likewise, views Tsuna as a friend, ever since Tsuna stopped him from commiting suicide. He generally accepts Tsuna as the Tenth Vongola, and seems fine with following Tsuna's leadership.
As Hibari is one of the most bloodthirsty characters in the series, Tsuna is often uncomfortable around him. At their first encounter, they fought with each other and Tsuna hit Hibari with a slipper while calling him a fool. Nevertheless, Tsuna generally feels more confident when Hibari is around, due to Hibari's deserved reputation as an excellent and merciless fighter. On the other hand, Hibari generally is aloof to Tsuna and initially thought of him as a herbivore. He mostly avoids Tsuna and the rest of the Guardians due to his dislike of "crowds," and views them as weak and not worth his time. However, in the Inheritance Ceremony Arc, before he fights Adelheid, he notices Tsuna making a 'boring face' due to the mental shock he received and tells him to watch his fight closely, which surprises Tsuna. This possibly means that Hibari has started acknowledging the current Tsuna. After he wins the fight with Adelheid, he says that "it is the sky that allows the cloud to move about freely." as further emphasis of his recognition of Tsuna. Considering that he is fond of small animals and acknowledges their will to survive, his description of Tsuna as a "small animal" may actually be a compliment. Hibari's overall attitude towards Tsuna can be quite teasing and even friendly at times, such as when he told Tsuna that he likes to throw snowballs at people, which made Tsuna wonder why he hasn't been arrested yet. In the Future Arc, he is revealed to be the only Guardian and one of only two people (the other being Shoichi) that Tsuna confided in, something that surprises even the present-day Hibari himself. Later in the same arc, when Hibari begins to spar with Mukuro and Tsuna stops them, Hibari seems amused and offers to fight Tsuna instead, but Tsuna declines.
Tsuna is often flustered by Ryohei's passion, and the confidence Ryohei has in his strength. He is often roped into fights alongside Ryohei (often schemes to get Tsuna into the boxing club), leaving Tsuna wondering how he could be Kyoko's brother. However, Tsuna values him as a good friend, referring to him as an older brother. Tsuna also shows reluctance whenever Ryohei fights, due to how his injuries could affect Kyoko.
Even though Lambo often drives Tsuna crazy, he seems to deeply care for him. Evidence of this can be seen during the Varia Arc when Tsuna saves Lambo from Levi A Than during their match for the Vongola Lightning Ring. However, during the Future Arc, Tsuna was beginning to succumb to the frustration due to their current situation and eventually snaps at Lambo and Haru saying that they don't know anything. They later reconcile when Tsuna apologizes to him. Tsuna always tries to put Lambo out of danger, believing it to be unfair for such a young child to be put to battle and always blames himself if Lambo is in a danger. Lambo, despite his constant mockery towards Tsuna, comes to regard him as an older brother figure, something that Future Lambo proudly stated when Large questioned him.
Tsuna initially hated Mukuro greatly for the horrible things he had done to his friends, in order to lure Tsuna out. After hearing about Mukuro's past from Ken, Tsuna lost his hatred towards him. Although Reborn often tries to remind him about those horrible things, Tsuna remains concerned over Mukuro's well-being, as seen in Future Arc when Tsuna knew that Mukuro is still trapped in the Vindice Prison after 10 years. He does not see Mukuro much of an enemy and worried whenever bad things have occurred to him. Tsuna is also the only person to know of Mukuro's good side and thus, always be the first one to doubt whenever everyone feels Mukuro doesn't care about his comrades. Mukuro, despite his great hatred towards Mafia, doesn't seem to hate Tsuna that much and even trust him enough to protect his subordinates.
She seems to appear out of nowhere with Tsuna in some scenes, though it could be coincidence. Chrome also likes Tsuna as he was the only one who trusted her to be his Mist Guardian out of everyone in the group for the Ring Battle and rewarded him with a kiss, much to his embarrassment. Despite Chrome's connection to Mukuro, Tsuna sees her as an important ally and shows concern for her health, such as bringing onigiri to her during the Arcobaleno Trials Arc. He thinks of her as an important friend, as one of the reasons he went to battle Simon was to rescue her, and he generally cares for her well-being.
You suddenly show up saying that you're a tutor and want to make me into a mafia boss! And then it's all just been a mess! You used your spartan training on me, made me confess my love to the girl I like against my will, dragged me out even though I didn't want to, and forced me to have fun or fight with people!! You made a disaster of my school life!! ...But... If I look back, even as close as yesterday... in the end I had fun... I really had lots of fun.
As the most trusted assassin of Vongola Nono, Reborn was sent to Japan to educate Tsuna and make him the true successor of the Vongola Famiglia. When the two first met Tsuna didn't take Reborn very seriously, believing that it was ludicrous to have an infant for his home tutor, he even laughed at the idea of Reborn's tutelage before he was brutally kicked in the stomch. He found Reborn to be an annoyance and disliked his bluntness and tendency to belittle him, calling him names, physically causing harm to him, and humiliation. After Tsuna was able to beat Mochida in a kendo match and become friends with Kyoko, he begins to warm up more to Reborn and begins to be more grateful for Kyoko and the other friends he met thanks to Reborn.
Tsuna is very wary of Reborn to his involvement with being a hitman in the mafia and often tries to avoid contact with him, due to Reborn's spartan methods of training, which more than often inolve Tsuna getting shot, facing danger, and being humiliated. He's shown to be one of the only people who aren't deceived by his strange antics such as his numerous costumes, being the only person to recognize Reborn in these costumes, and his nonchalant acts of violence. In spite of Reborn's cruel and unusual shenanigans and Tsuna's lack of tolerance for them, the two share a teacher-student relationship and are rather close friends. Their relationship has brought about a drastic improvement in Tsuna's character, helping him become more confident and the ability to lead the Vongola, something that Tsuna and his allies recognize.
When Reborn is sent into the future, via the Ten Year Bazooka, Tsuna grows extremely concerned over Reborn and wonders why he hasn't returned from the present even after being gone for longer than five minutes. His concern for Reborn only continues more when Lal Mirch informs him that the Arcobaleno have all been killed in the future. When he finally reunites with Reborn in the hideout, Tsuna is on the verge of tears and tries to hug Reborn, until it's revealed that Reborn was really a decoy, and the real one comedically attacks him from behind.
The true extent of their bond occurred during the Representative Battle of the Rainbow when Reborn considered joining Bermuda von Veckenschtein to stop the Arcobaleno system. Tsuna lashes out as Reborn for his decision, going further to say that he caused Tsuna a lot of trouble and isn't qualified to be a home tutor, even challenging him if Reborn goes through with the decision. In the end, Tsuna refuses to let Reborn die. When Bermuda was defeated, Reborn finally realized that now was the time for Tsuna to decide whether or not he wants to become the Tenth Boss of the Vongola. As usual, Tsuna declines a fate tied with the mafia, and Reborn returns back to Italy no longer needing to train him. He goes an entire week without the presence of Reborn and comes to the conclusion that he's barely changed since the beginning of their tutelage. Reborn returns back to Namimori, revealing that he would now train Tsuna to become the Neo Vongola Primo. In the end, Tsuna realizes that he has changed since he met Reborn because he now has many great friends that he can rely on.
Ever since the beginning of the series, Tsuna has had a deep-set crush on Kyoko after being the only girl to ever talk to him. He saw her as the "coolest girl in school", was the only reason to attend school, which is an otherwise humiliating experience for him, and even skipped school when he believed Kyoko was in love with Kensuke Mochida. With the involvement Reborn, he quickly catches her attention, albeit with publicly embarrassing himself as a result of the Dying Will Bullet. At first, Tsuna thinks that Kyoko would hate him after being forced to confess his feelings to her, but she believes that it was a joke and apologizes for not understanding the joke.
The two quickly progress to a deeper friendship, though it possesses a certain chemistry that only Reborn, and Kyoko's best friend, Hana, seem to see. Kyoko is someone that Tsuna holds near and dear to him, going through great lengths to protect her, keeping her away from the mafia world, and is even willing to sacrifice his life for hers during his encounter with Birds and the Bloody Twins. He covets a protective charm received from her; Kyoko later sews him a pocket on his clothes so he won't lose it. In the Future Arc , he panics and chases after her when Bianchi tells him she is leaving because of being left out of the loop; ultimately, he tells her about the mafia and is aided in his training when Kyoko observes that the behavior of Tsuna's Vongola Box is much like his own.
Twice in the series, Tsuna has been forced to confess his feeling towards Kyoko , with the help of Dying Will Mode, but have failed twice. In the beginning of the series, he confesses by accident, with Kyoko simply under the impression that it was a joke, and again at the end of the series, where Tsuna's confession is interupted and he needs to save Haru, Lambo, and I-Pin, with Kyoko only reaffirming her friendship towards Tsuna. Although Kyoko obviously views Tsuna as a good friend, it remains up to speculation whether she reciprocates his feelings. In the future, the older Kyoko briefly refers to Tsuna as "Tsu-kun", though an explanation on why was never given.
When the two first met, Haru had disliked Tsuna, as she was under the impression that Tsuna had corrupted the mind of Reborn with the mafia, to the point where she would physically harm Tsuna because of this. After being rescued by Tsuna from drowning, with the use of Dying Will Mode, her opinion changed and she gained a deep one-sided admiration for Tsuna.
She is a bit over enthusiastic towards Tsuna, who is in return bewildered or embarassed by many of her antics. Unlike Kyoko, who remained oblivious to the mafia for most of the series, Haru was more aware of Tsuna's position in the mafia and his role as the Tenth Vongola, and seems to love him more because of it.
The two had a falling out in the Future Arc, with Tsuna taking his anger and fear towards Millefiore out on Haru, whom he yells at for being oblivious to the fight against Millefiore and not knowing anything, despite Tsuna never giving her an explanation and leaving her in the dark, Haru, in tears, states that she was willing to listen to Tsuna if he ever tried to explain anything, and she leaves the room crying. Tsuna later apologizes to Haru, after realizing how much Haru and Kyoko have helped them while in the future, and the two rekindle their friendship. While Haru has a crush on Tsuna, he only sees her as a good friend due to his feeling for Kyoko.
They are not on good terms, Xanxus hates Tsuna and has never openly acknowledged him as the true successor of Vongola, which is why he and the Varia only take orders from Timoteo. He was the only one who refused to attend Tsuna's Inheritance Ceremony. Tsuna was at first scared of him and thought that he should be the Vongola boss instead of him. However, this changed after he realized what kind of person Xanxus is, especially what he did to Timoteo, and became determined to prevent him from succeeding the Vongola. However, despite this, whenever the Vongola are attacked by outsiders, they put aside their differences to work together and as stated by Xanxus, the Vongola always fight as one.
Tsuna and Byakuran started off as enemies because of what Byakuran had done to the Vongola and its allies. Tsuna has shown his desire to defeat Byakuran at all costs numerous times and his resolve only deepened after Uni sacrificed herself to revive the Arcobaleno and Byakuran insulted her actions. Angered, Tsuna then stated that he wouldn't forgive Byakuran and went on to kill him.
Byakuran has also shown his annoyance over Tsuna's interference in every parallel world. However, in the present, they seem to be much on better terms, since Byakuran has had a change of heart. He even offered Tsuna an alliance with his team and protected him when Tsuna was almost hit by Collonnelo's attack. It is unknown whether Tsuna has fully forgiven him or not for what he had done in he future, but Tsuna seems to regard him as a comrade after they fight together during the second day of the Representative Battles of the Rainbow. Tsuna was concerned when Byakuran was injured by Colonnello's attack, prompting Tsuna to promise that he will defeat Iemitsu. Sometimes Tsuna finds Byakuran's cheerful attitude to be odd and admits to not knowing much about him. According to Uni, Tsuna and Byakuran are similar in a way both of them don't understand.
Enma has demonstrated in multiple ways that he is similar to Tsuna; likewise, Tsuna thinks of him as a good friend. However, after Tsuna unknowingly failed the test he had set up, their relationship became strained, making Enma believed that Tsuna is no different from the cruel Vongola bosses. After Enma and his Famiglia stole the Vongola Sin, their relationship worsened, as Enma claimed that he would never forgive Tsuna and would no longer have any hesitation to kill him. Tsuna stated that he is also angry at Enma for making his friends suffer, and also for insulting Giotto, but he also sympathized Enma's past and current condition, as he still regards him as his friend. After witnessing from the fourth and fifth keys that Cozzato was never betrayed by Giotto and saved Enma from Demon Spade's control, they reconciled, becoming friends again. Not only restoring their friendship, this incident also deepened their trust towards another, as Enma stated that he believes Tsuna would never betray him.