For once this won't be there "Kadowaki this is why we can't have nice things" discussion...it'll be HARUNAWA THIS IS WHY NO ONE LIKES YOU discussion. To be fair I don't think he cares if anyone likes him or not, but the fact still remains this is why no one does.

Really bad timing when it comes to all things romantic: Arata and Oribe are having a relaxing time at Oribe's Uncle's resort...Harunawa shows up to interfere with their (almost not quite) confessions, mess with Oribe's cousin and then chase them around before butchering a whole bunch of people.

Rather specific kind of humor: kekekekeke I don't kill the folk I encircle with Bakuto - they become new tattoos for my skin and disappear, how amusing right? NO HARUNAWA NOT EVEN A LITTLE.

No Sense of Fair Play: I found you because someone who helped you was walking along and happened to know about your whereabouts - did I kill this person? Who knows! Probably? I don't care enough to say!

Meanwhile I have to hand it to both Hinohara and Arata - those two take the cake for dense when it comes to females. Granted Arata technically only has Oribe to understand, but he doesn't quite seem to understand when she looks sad at his apparent over enthusiasm for her to return home with him. And Hinohara? OH MY SWEET SHINY STARS HINOHARA. If he's not martyring himself at the throne of "I keep fucking up" he's alternately unable to understand why Kadowaki would try to save him, only to try to kill him, only to save him all over again and wondering why him constantly discussing Mikusa coming back to Japan with him would make Kotoha (who he has feelings for!) upset.

Look all I'm saying is its a bad day when Kannagi is left to cheer up Arata and tell him he did a good thing okay?

Honestly if it wasn't for the fact I don't think Watase writes intentional yaoi or shonen-ai (a case can almost be made for Nuriko and Hotohori, but that was very one-sided romantically) I'd think Kadowaki and Hinohara's issues stem from the fact one loves the other and felt rejected. Their fighting has taken on a very friends to enemies to lovers vibe:

Hinohara: Kadowaki I want us to be friends!
Kadowaki: NEVER! I WILL KILL YOU!
(new enemy appears and beats Hinohara up badly)
Kadowaki: YOU CAN'T TOUCH HIS PERFECT SHINING HEAD! (defeats new enemy)
Hinohara: Kadowaki you are my friend! Let's work together!
Kadowaki: NEVER! I WILL KILL YOU! (runs off to sulk)
Everyone else: You're really throwing around a lot of mixed signals here.
Kadowaki: SHUT UP! IT MAKES SENSE!

Though to be fair I haven't read a whole lot of shounen over the years (the shounen I do read tends to be...very violent and/or psychological. For example: 20th Century Boys, Yu Yu Hakusho, Until Death Do Us Part, Gantz) so this could be totally normal behavior for all I know. ( )