- When the series begins, the one thing that keeps Kenichi returning to the dojo for his hellish training is Miu. Miu is the one dojo resident who acts like a regular human being and treats Kenichi as such. During a period where Kenichi is trapped in his own quarters overnight at the dojo, Miu beckons him over to the rooftop in her jammies so they can have a picnic and look at the stars. Awww.
Miu: Kenichi, I would like it if we could be friends for a very long time.Kenichi(Thinking): You know, I'm pretty sure she just told me I have no shot at being her boyfriend.(Looks up at Miu's smiling face.)Kenichi(Thinking): But you know, I think I can live with that. For now."Cue the awesomely heartwarming credits music."
- When Apachai literally comes Back from the Dead to save Kenichi.
- And later, this line from Koetsuji when he was desperately trying to save Apachai: "I won't give my precious friend's life away to a mere God!" And he DOES save Apachai.
- Any time Apachai plays with small children or Honoka, or interacts with small animals, it is pure, unfiltered adorable.
- Kenichi helping Takeda to get him out of his hellhole gang life and revitalize his boxing career.
- When Kenichi's father decides to raid Ryouzanpaku to "save" Kenichi. Sakaki catches up to them and Kenichi's father moves to protect him by punching Sakaki. When asked why he didn't dodge the punch, he responded with "To protect his son, a father throws a punch with all his power, if I dodged it, then isn't that too rude?
- This chapter altogether. Scratch that, any interaction between Honoka and Tanimoto is a plain CMOH.
- When Kenichi faces a master weapon-user alone to buy time for his friends' escape, the Ryouzanpaku masters scold him for nearly throwing his life away and send him to his room. But they're really secretly proud of his growth as a martial artist and as a man. Kenichi cries with happiness.
Kenichi: Honestly... those masters of mine...
- This wonderful exchange:
Kenichi: "Actually, there's a feeling inside me that I want to express in words, but... I want to keep those words until I'm able to protect you. For now, all I can say is that I have that feeling inside me... Do you think I'm a coward?"Miu silently shakes her headMiu: "Because... if that's so... until now... not by your words... but by your actions... you have already told me. That's why... I will also... [do the same] with one action...Miu proceeds to kiss Kenichi on the cheek!Or she would've if not for the Ryouzanpaku Masters' Moment Killer.
- Chapter 58, when Miu is depressed that she has no parents to take to the play she's in when everyone else in her group can. All of the Ryozanpaku master's solution is to dress up and go as a surrogate family for their daughter.
- Chapter 380.
- The whole of Chapter 406. "I will protect him even if I die," in-fucking-deed!
- Chapter 448 is pretty much one giant Heartwarming Moment. Kenichi has just had Miu kidnapped, and is so down in the dumps about it that he starts literally beating himself up over his failure to protect her. Cue not only the Shinpaku Alliance rallying around him, but the Yomi members at school offering moral support as well. Chikage does it in the form of chocolate!
- Chapter 465 is this wrapped up with awesome. Miu and Kenichi have little celebrations of her having been brought out of Junazard's brainwashing even as they take down the insanely powerful swordsman Kenichi's been fighting thus far.
- Chapter 496: Takeda is preparing to sacrifice his healed left arm to a YOMI submission/counter specialist so he can deliver a devastating punch with his right. Ukita desperately tries to get the others to stop him, not wanting Takeda to throw away everything he's gained back, but the others don't move, not wanting to interrupt the one on one fight. Finally, Ukita rushes forward, shouting, "If no one stops them then I will!! Before being a martial artist, I AM HIS FRIEND!!" This inspires Kenichi to break the fight before the YOMI breaks Takeda's arm.
- Chapter 519: All of the Shinpaku's efforts on Defusing The Tykebomb Chikage Kushinanda have finally payed off. At one point, Kenichi asks Chikage, should she decide to stay with YOMI, to remember the times when they were friends. She does, and the results are adorable.
- Chapter 539: Mixes this with awesome. Shigure, alone, faces seven masters, just so Miu and Kenichi will be safe. It didn't work, but the intent was amazing.
- When Tanimoto loses consciousness during his fight Chou Enshin he (predictably enough) see's his dead little sister telling him not to "sleep here." Then he sees Honoka, his Replacement Goldfish, asking him to play Othello. Cute, but far from unexpected. Then he sees Kenichi telling him that "it's dangerous if you sleep here!" Aw, he really does care!
- Niijima's sincere email to Kenichi in which he compliments Kenichi on everything he's accomplished and how he made him change his worldview regarding everybody having a predestined role in life.
Heartwarming / Kenichi: The Mightiest Disciple
For a badass shonen series on martial arts, a lot of heartwarming moments occur nearly once an episode.