hero & heroine.
You're my hero, dude... And my best bud!Kanji shares a special relationship with many different characters in the investigation squad, however there are two that seem to bring about and shape his character throughout the game: his riverbank escapades with the protagonist, Seta Souji and initial meeting (and later awkward incidents) with detective Shirogane Naoto.
The FoolThere is probably scientific evidence pointing to the fact that Kanji looks up to and thinks very highly of his senpai--he treats him with the same respect that he treats his own mother and owes him a lot for the hand he extended when Kanji felt like he had really hit rock bottom. Though Kanji had started to gain acceptance of his shadow self after he was rescued from Mayonaka TV, it was only through Souji's guidance that he was truly able to figure out where his problems lie and who he really was. When the entire school and town couldn't look at him as anything but a bully, Souji was the only one to give Kanji what he had been looking for all along: trust and acceptance. He was willing to believe Kanji when he said he was innocent of bullying other students, and even went out of his way to help Kanji better understand all of the confusion bubbling around in his head. Throughout the game, Souji is one of the few who never doubts Kanji and understands him for who he is: during the school trip, although Yosuke is hesitant to let the possible flaming homosexual into their tent, Souji's more than willing to scoot over and give him a place to stay.
And just like Souji is willing to stand up for Kanji, Kanji is also willing to protect his senpai: he'll take hits for him in battle, and is even brave enough to stand up to the police to make sure that he doesn't make his senpai into a liar. Kanji's mother is also extremely fond of what the hero has done for him: when she meets up with Souji at the hospital she admits that she's happy to see Kanji is making friends with boys like him, and later thanks him for being a good influence on her son. For Kanji, Souji is really the first person who he's able to open himself up to and admit all his weaknesses to, but ironically, his strengths as well, as Kanji had been hiding his talents and good nature from everyone.
Kanji: Senpai I'll be waiting for you .... I'll do my best! You better not run away too, senpai!By opening himself up to a friend, he was able to mature and find the bravery to open himself up to the rest of the world as well. It's clear through Kanji's resolve that he has all the thanks in the world for Souji's understanding, and plans to continue doing his best to make sure that others understand him, just as he promised to him during the last day of his social link.
FortuneKanji's relationship with Naoto is a complicated one: though she's a character that doesn't have an introduction until very late in the game, we meet her very early on when the investigation team decides to spy on Kanji to get more information about Mayonaka TV. Kanji is caught having a conversation with her, but because of Naoto's appearance and disposition she's mistaken to be boy. This causes a lot of misunderstanding: not only for Yukiko and Chie who are giggling at him, but for Kanji's feelings-- if Naoto is a boy, and he's a boy, what does that make him? Because Kanji is overly concerned with being "manly", he's worried at the thought of having feelings for Naoto and gets defensive with Chie and Yosuke bring it up. After all, the last thing a kind-of-girly man wants to add on to his resume is "homosexual". Naoto's presence at Kanji's entrance in the game marks one of the pivotal problems in his social link: gender and sexuality. Perhaps the interesting thing about this is the fact that these two characters share similar gender problems: Naoto is a girl struggling in a woman's world and thus acts like a guy, Kanji is a guy struggling in a man's world because he's secretly more like a girl.
That being said, it's pretty clear that Kanji sympathizes with Naoto's problem more than anyone else does when they meet her shadow at the Secret Base: both of them are dealing with gender roles that have been setup by society--rules and boundaries that have been placed upon them that are not necessarily right or wrong. As he listens to Naoto yell at her shadow, claiming that it isn't who she is, Kanji holds back the team as if he understands how important it is for her to come to terms with the truth.
Kanji: It's okay, just let the kid spill the whole thing. If not, Naoto's just gonna keep hurting...
As soon as Naoto joins the squad and Kanji is aware that she's actually a woman, he becomes something like an awkward, fumbling, blushy teenage oaf. Unfortunately for him, no kind of relationship ever comes to fruition (if even only because Naoto is a datable option for the main character), but he has his own small way of showing his affection, no matter how silly and high-school crush it may be: he cheers her on during the Miss Yasogami High pagaent, he supports her when times are rough, and though they are in the same grade, it's clear he respects her as someone who's mature and very intelligent. (Though he does call her a dumbass for recklessly going into the TV world: it's definitely out of the goodness of his heart.)