(Here's what i draw for the video if youre curious

Hajime is allergic to peanuts, he never tell anyone because he just assume that it was unnecessary info, till when he ate something kazuichi made to him and he fell on the ground, almost dying

Fuyuhiko HATES yakult, as lactose intorelant, he had to drink it very often, mostly as a child and he absolute hates it

Hajime hates physical touch, but he pretend to like it, Fuyuhiko loves physical touch, but he pretend to hate it

Fuyuhiko can tell if izuru is the one talking easily, sometimes people go and say things like "hajime is acting so different today", he stares and just say "probably because it isnt fucking hajime"

hajime smells just like those baby soaps, he rarely uses perfurme, fuyuhiko like those expensive perfumes, he really likes those, specially the strong ones, but he rarely uses them either, because he is embarassed to

Both have shitty families on different ways (btw, this isnt fully headcanon, most of this topic is in fact canon) fuyuhiko's family is violent, they often fight, to the point of death threats between his parents, he had to grow up in an extremely hostile enviroment. Hajime on the other hand had parents who were neglectful, they probably just didnt care about him, his urge for feeling special probably came from this, hajime's parents wanted a trophy, not a child, and they probably let hajime do a LOBOTOMY because, 1 - he would finally be useful, and 2 - his presence wont be missed

Hajime and fuyuhiko both have a hard time sleeping, they spend the night awake talking to each other, sometimes they fall asleep in the middle of the chat, other times they just spend the whole night awake

hajime loves talking about his interests, but never got the chance to do that, once fuyuhiko found out about this he made hajime talk to him about it for hours, fuyuhiko actually make good commentary about it and seem to actually care and get his excitement, which makes hajime happy

Hajime and fuyuhiko are both overworkers, and always call out for each other, even thought they do the same mistake

Fuyuhiko is totally Japanese, hajime isnt, as thought as he is Japanese descendant, he is also latin American, specifically brazillian, he was on brazil between the age of 0 to 10, he then moved to japan, even if it was pretty early on his life, hajime likes the dishes from his homeland and make fuyuhiko try them, fuyuhiko fell in love with the brigadeiro, which was sweet just like he likes, hajime makes them often for him, sometimes when fuyuhiko is alone at his Office he eats them

Just like fuyuhiko like sweet things, hajime doesnt mind food, but he like bitter and spicy food, like REALLY MUCH, fuyuhiko thinks he is insane to drink Juice without sugar or to eat so many spicy things without a cup of water, i guess hajime's favorite bitter thing is...fuyuhiko! I love this analogy, like hajime is a sweetheart and fuyuhiko like sweets, its only far for the opposite to happen!

hajime when he gets mad he often stop talking and just ignore the person he is mad about, fuyuhiko not only mock him and his angry mood, but he often treat the person equally bad, he didnt even care about the motive, he just did, fuyuhiko didnt ask why he was mad thought, he knew it was frustrating hearing this type of question, but still he says things like "just say how much of a bastard this piece of shit fucking is! I have no idea what this mother fucker done but if youre mad it must been pretty mess up"

They like to watch EVERYTHING togueter, hajime is the type to say "no...please dont do it *character* dont do it youre gonna to die dont do it" for the TV, fuyuhiko is the type to "STOP GOING THERE ASSHOLE YOURE GOING TO DIE, COME BACK. COME BACK." In the end the character die and they both stop talking, but probably thinking the Same thing, that it was the most obvious thing ever

Fuyuhiko relationship with izuru is...weird, they often dont talk, they spend their time in silence, which is often more comforting then scary, fuyuhiko sometimes Braid izuru hair, fuyuhiko is aware izuru is just a repressed version of hajime, even if people try to make them different persons

And for the final headcanon, izuru wakes up early at 9:00 to watch mikudayo show, for some reason he likes it, he watched it in the past, and had a few memories that he didnt remember, so he started to watch those episodes everyday, the first time fuyuhiko saw him doing it was like "huh, hajime what are you doing awake right now" to realize it was izuru, he then see the mikudayo program and gets confused, how could izuru like it, he just silent watched too, fuyuhiko now likes the mikudayo program, he just dont admit to anyone

Natsumi one was so hard to make...