Oh, you've come to the right place my friend 🌴🦦👓 (imagine an otter adjusting its glasses haughtily like Keito). I do do headcanons! And with Kanata, a lot of what I like about him and Akatsuki is the room for potential he has with them!

🦦📿 Kanata and Keito | So many. Too many. But I'll be fair to the rest of AKATSUKI and keep it brief. The number one dynamic I envision for them is what I like to call "bad guy hero" and "good guy villain". Keito puts up with a lot of antics in his day-to-day, and he'll just like... adjust his glasses and scold, and then just be like "Well... I suppose that's fine." Meanwhile, I think an underrated characteristic of Kanata is he's just kinda... really brutal, it's funny? He ushers sea creatures into a bucket like "let's have a race~ omg my beautiful babies you did it~... time to race in my tummy (: " Like he's just so funny, and Keito's capable of dealing with literally all of it in a straight-man kind of way. Many Minds, One Flower shows this best.

(My abridged TL)
Keito: Shinkai. What is that?
Kanata: it's ikebana of course, from the school of shinkai~
Keito: No matter how you look at it, all you did was stick a fish onto the needle bed
[Conversation, conversation]
Kanata: Anyways, I'm done, bye.
Keito: Tch... [Delivers a dumbass pun] It's a coral arrangement, not a floral arrangement. Guess I'll go put that in the kitchen.

LIKE, KEITO?? THROW IT AWAY. WHAT THE HELL.

That's my favorite dynamic for them, it applies in canon (Intelligence, Disclosure Ch. 4, Kanata investigating the mystery of Mendako aliens, Keito just kinda like "well, let me know how that goes."), and it has so much potential outside of it. They have unexpected contrasts that play off each other well, and I think that gets underestimated when you only think of them under the Meteor Impact lens.

I have to move onto Kuro and Souma for the sake of fairness, but if you want more headcanons, here's a fic about them teaming up in volleyball that goes into more underrated, compatible aspects of Keito and Kanata, like Keito's childish/competitive personality, and Kanata's pride and bulky stature. Also featuring Kuro and Chiaki: https://archiveofourown.org/works/57490381

🦦🐯 Kanata and Kuro | They're one of those relationships I'd like to see a lot more of. They have this vibe where they could make knowing glances at each other behind Chiaki's back ("Oh, you know how he is"), and they're tall so it's over his head, and he has to peek up (":3 what are you talking about?") and they're like "nothing~/nothin'". I bet they team up on him a lot, and if there were ever something they wanted to peer pressure him into, they could do it. They also have a lot of themes of maternal-ness around them, so it would be interesting to explore that aspect of them just having comfortable, nurturing silences together bc being together doing nothing is better than being alone-- like how Kanata's just kinda lying around on the dojo floor in Comic World because he wants to hang out, and Kuro's like "Yeah, it's cool." Does Kuro just kinda sew next to Kanata's fountain while Kanata floats around. Or like.

Kuro: Whaddya think of this. [Shows him his work.]
Kanata: i'm hungry...~
Kuro: Very cool, Shinkai. [Thinks it's fucking hilarious.]

Also, Kanata's canonically huge and strong, I have a few sketches where he completely suplexes Kuro, like...

Kuro: Heh, alright Shinkai. Don't say I didn't warn ya--
Kanata: hup~ [Completely throws him over his shoulder and pins him down with his knee]
Kanata: :3c

Give me more Kanata bodying people. Give me Kanata and Kuro wrestling like cats when Kanata says something cheeky, and Kuro knows he's capable of a good grapple. THEY HAVE LOTS OF POTENTIAL, I LIKE THINKING ABOUT THEM.

🦦🐴 Kanata and Souma | Obviously, they've got the most substantial relationship of the three. I think because they have a lot of canon together, it's harder to headcanon, but in my dreamspace, I like the vibes of a non-god-and-weapon AU childhood friends. Submarine was great because seeing them interact as like... people-people... Souma having his own assertions and ideals he can TELL Kanata because they ARE equals. They are IDOLS. Let them have plain fun like children. Let Souma scold him like "Shinkai-dono..." and Kana be like "Eto bwehhh."

I like Kanata being a bit of a tyrant with Souma, the difference between him and Keito as Souma's lords is a fun thing to play off of because Keito's like "he's my pwecious kanzaki weave him AWONE" and Kanata's like "anyways" (strings souma up and throws seaweed on him). Bully Kana is peak, and Souma is a good role for that. However, I like it more if Souma can be cheeky back with him like he gets with Keito. Less "I'M SORRY SHINKAI-DONO" and more "SHINKAI-DONO LET ME KNOW PEACE >m<!!! PLEASE, YOU ALWAYS DO THIS."

For some headcanon scenarios... Them both trying something new for the first time that they're both fish-out-of-water about it. Like maybe trying to operate some kind of technology or vehicle, and Kanata's like "... i'm bored" (doesn't like wasting time on things that aren't going anywhere) and Souma's like "NO, SHINKAI-DONO. NOTHING VENTURED, NOTHING GAINED!" (has made no progress) and Kanata makes that one Todomatsu face in frustration as the sun climbs higher and the air gets drier.

🌴 So yeah, those are my AKATSUKI x Kana headcanons. I have literally SO MANY MORE HEADCANONS BETWEEN AKARYUSEI SO SO MANY I WOULD WRITE THEM ALL DOWN BUT I WANNA MAKE SURE I ANSWER THIS QUESTION IN A PROMPT AMOUNT OF TIME, BECAUSE TRUST ME, I COULD AND HAVE SPENT HOURS ON ANSWERS. So I'll make this about Kana for now heheh. I hope you enjoy anon, and I'd love to hear yours!