Kaburagi and Danchiku are childhood friends who work together well as cyclists. Before entering Sohoku, the two were members of a cycling group called "Team SS" or "Team Speed Shot." Kaburagi relies heavily on Danchiku for support, both physically as a cyclist and emotionally as a friend, a relationship exemplified when Kaburagi was forced to ride alone during the Training Camp. He was at a loss until Danchiku passed by and encouraged him. Danchiku does not appear to have any hard feelings about Kaburagi being the only one to make the Inter High team and instead offers his full support after he tried to use his bad attitude of relentness nagging to try getting what he whats into this battle within himself.
Second Year Events
When Teshima sends Aoyagi and Kaburagi out to take the sprinter checkpoint on the first day of the 42nd Summer Inter High, they learn that Kaburagi still does not consider himself a sprinter. Ignoring Kaburagi's protests, Aoyagi grabs him and pulls him along. When Kaburagi is rude to other, older cyclists, Aoyagi apologizes to them. Aoyagi appears continually surprised at Kaburagi's mistakes, such as when the latter reads zekken incorrectly. When they face Doubashi, Aoyagi feels threatened but is once again surprised to see that Kaburagi does not seem affected at all. Despite all this, Aoyagi thinks that Kaburagi has great potential as a sprinter, and even imagines introducing him to Tadokoro. He manages to convince Kaburagi to compete against Doubashi for the final sprint by using the same stationary Kaburagi associates with the "god of Orange Beena" (who is really Aoyagi). Though Kaburagi loses, Aoyagi is nonetheless proud of his efforts.
Kaburagi's first meeting with Onoda was on the first day of the school year when he didn't know what Onoda looked like. He grabbed Onoda, ignorant of his identity, and declared that he intended to surpass the amazing "Onoda-senpai." Later, Kaburagi apologized for his mistake. Upon observing Onoda's appearance and behavior, Kaburagi was disappointed because he expected more from him as a senior as he doesn't act like one. However, he learned through experience that Onoda is a skilled cyclist. Now he has more respect for Onoda than he does for Imaizumi or Naruko.
Imaizumi and Naruko both see Kaburagi as an arrogant underclassman whom they don't want to lose to. After being "forced" to let Kaburagi take first place at the Inter High Qualifiers, they complained together just loud enough for Kaburagi to overhear. This is also when they give him the nickname "hothead/showoff." The two found something new to bond over: making fun Kaburagi. They don't seem to genuinely dislike him, though. But according to the omake in the 12th episode of season 3, Kaburagi may not like them, at least he doesn't like them as much as Onoda.
Second Year Events
Kaburagi and Doubashi's first meeting was disastrous. Kaburagi was experiencing stress-related stomach pains before his debut Inter High (perhaps Danchiku's problem rubbed off on him), so he searched for a toilet. Unfortunately for him, there were no open toilets. He desperately pounded on the door to an occupied stall, greatly annoying the person inside, who happened to be Doubashi. When Doubashi exited the toilet, he confronted Kaburagi. However, Kaburagi was so uncomfortable at this point that he yelled at Doubashi to let him "take a shit first." After relieving himself, his argument with Doubashi continues. Doubashi plants a seed of doubt in Kaburagi's mind by insulting team Sohoku, saying that perhaps they are not as strong as Kaburagi thinks. When Kaburagi and Doubashi meet again later during the sprint battle, Kaburagi calls Doubashi "pig" and Doubashi responds by calling him "orange." Kaburagi doesn't understand the meaning behind the zekken numbers and mistakes Doubashi for a "backup" member. This understandably leads Doubashi to think that Kaburagi is a bit dumb.