They start fusing from a distance after that. They also train unfusing. Training takes over their days but they don't mind, it makes their time pass easier. (Midoriya-kun also keeps tinkering. Hitoshi doesn't really ask.)
Slowly they work on improving the range of their distance fusion. At first they had to be close and nearly touching for it to work, but with time and work they made it happen from a metre, then more, until they're in shouting distance and still capable of fusion.
The bubbling, fuzzy feeling is addictive, even more so when they can access it at any point.
They made a game out of it, focusing it in their hands, or legs, or heads and trying to get them to glow without other body parts. They succeeded after a few weeks.
They also figure out that the glow only happens a few seconds after the fizzy feeling starts. And isn't that a research of the day? After that they make it a game to do it in class, almost fusing but never fully while the lesson goes on.
Time passes fast when you have things to do. They almost don't pay attention to the bullying, or rather they do their hardest to ignore it. It kinda works. Most people stop their behaviour after some time. Bakugou and his little gang don't, but it's nothing either of them hasn't dealt with.
Before they know it, it's exam time and they have to sacrifice their precious fusion time for last minute studying. But it's alright, they're alright.
They both ace the exams, and watch as Bakugou explodes in anger for being overtaken in rankings.
Hitoshi can't help but find the situation hilarious.
Vacation starts soon after and they both take a breath of fresh air as they are freed from school.
Midoriya-san attends the graduation ceremony, and cries as both Hitoshi and Midoriya-kun get their grade school diploma with distinction. They go get ice-cream afterwards. It's a good day.
It turns into an even better day when they get home. Midoriya-san disappears into her room for a minute and reappears with two packed presents. Hitoshi's breath hitches. If any of this is for him, it's going to be the first time he's gotten a present since Akiyama-san gave him the indestructible phone.
Midoriya-san takes a present in each hand and gives them to him and Midoriya-kun at the same time. Hitoshi almost vibrates with excitement.
"Thank you, Midoriya-san," he says, tearing up a little.
Midoriya-kun just throws himself at her and hugs her tightly.
"Only the best for my boys," she replies, ruffling first Midoriya-kun's hair then his.
Hitoshi opens his present and it's a laptop with high ram and memory and all the basic school software that he'll need installed. There's also a Steam giftcard with 10000¥ scribbled on it.
His watering eyes turn into water taps. "I… Thank you so much—" he chokes out.
Midoriya-san smiles at him kindly.
Midoriya-kun laughs at him, pointing at his tears and says, "See? You'll fit right into this family."
Hitoshi wants to snap at him, but Midoriya-kun is already opening his gift and suddenly he turns on waterworks himself as he looks at his brand new Super Limited Edition Bronze Age All Might figurine.
"Mom! You didn't have to!" He hugs her a second time.
Yeah, it's a happy day.
In the afternoon he and Midoriya-kun go to Dagobah and sit at the shore of the cluttered beach with lunches lovingly made by Midoriya-san.
They just sit in silence, smiling. For once not trying to fuse. But once they do start a conversation, somehow the subjects of fusion drifts into it.
"I want to introduce Diana to my mom," Midoriya-kun says.
Hitoshi… isn't sure about that… but Midoriya-kun looks so carefree, so full of happiness at surviving grade school…
"Okay, we can do that. Today?"
"Today." It's a promise.
They enter the apartment quietly and find Midoriya-san in the kitchen, making tea.
"Oh! You're back already?" She nearly jumps when she finds them behind her. "I thought you'd be out like usual."
"Well… Mom, we'd like you to meet someone," Midoriya-kun says carefully.
Midoriya-san blinks at them slowly, but nods, looking around.
Hitoshi effortlessly starts on a fusion and feels Midoriya-kun do it too, the buzzing overtakes them and they join as Diana.
She's nervous. She's very nervous. But she's also very happy.
"Hello," she says, smiling brightly at a bewildered Midoriya-san. Mom. Uh. She has no idea what to choose. Whoops. Mamadoriya? Mamadoriya. "I'm a fusion of your sons!"
Mamadoriya's jaw metaphorically hits the floor. And then she starts bawling. Before Diana has time to react, Mamadoriya throws herself at her and hugs her tightly.
"You fused! I…" She looks at her again, completely in shock, and asks unevenly: "Uh, are you, uh, are you a girl?"
"Yeah, none of us three knows how that happened," she laughs, and Mamadoriya slowly blinks at her again.
"You… three?"
"Oh, I meant Izuku, Hitoshi and me! I'm separate from them," she informs. "I'm Diana by the way."
Mamadoriya silently cries for a moment before hugging her again. "It's very nice to meet you Diana."
Yeah, it's a good day.
Mamadoriya has a million and one questions; when did they start fusing, how are they so good at that, did she imagine it or did they fuse without touching? Diana answers all the questions with a smile, conveniently avoiding the topic of forced fusion. Not that Mamadoriya asks, she has no reason to suspect anything.
In her eyes the fusion is perfect, and that's all Diana asks of her. To not ask too many questions, to not look into it too deep. To just be happy for them and supportive.
And Mamadoriya is.
Diana laughs one last time and unfuses.
Hitoshi is a little miffed. Things are going almost too smoothly. But he's also weirdly at peace with the situation.
He's in his room now, him on the bed lying down with bent legs, his new laptop on his lap, just doing fuckall.
He sighs and lets his head fall back on the pillows a little more comfortably.
Midoriya-kun is also in his room, probably polishing his newest figure like the rabid fan he is.
'Hey, I'm not rabid!'
Hitoshi almost jumps out of his skin.
"You shouldn't hear me, it's been hours," he says to the empty room, heart rate picking up. He knows Midoriya-kun can hear him.
'I don't know what happened either, it's been silent then suddenly I hear you calling me a rabid fan— Wait. You can hear me now?' It shouldn't be possible. The only times Hitoshi has ever heard anything from Midoriya-kun, it was right after fusion, and usually emotions, not thoughts. Yet he can hear him clearly.
There's a crash, followed by quick footsteps, and Midoriya-kun appears in his room, eyes as wide as the smile on his face.
'Can you hear me?' he thinks, and Hitoshi can hear him. He nods. There's a moment of silence and Midoriya-kun gasps happily. "We developed selective mind-reading!"
"What," Hitoshi asks oh so eloquently. He's still caught up on the fact that he can hear anything from Midoriya-kun.
"It means that we can hear each other when we think at each other!" Midoriya-kun beams. "I can't hear you unless you think something directed at me, and vice versa!"
"That's… useful."
"That's amazing!" Midoriya-kun throws himself at him and hugs him. Hitoshi stands frozen for a moment before closing his arms around the boy's lithe form.
Hours later he still thinks about the hug as he's falling asleep.