Canon compliant AU where after a big fight with lots of injuried people and a pretty high dead count, where for the most part the allied forces (Cleaners and Hell's Guards) were incommunicated, Zanka goes up to his exhausted + hurt siblings (he's in pretty rough shape too) and asks for a favor from each of them.
Kyouka looks at him for a moment then asks what he wants, supposing is something related to the Cleaners. Zanka asks her to stay still for one minute. Kyouka supposes he's going to take advantage of her weakened status to injure her somehow (she, too, has a mean streak) and goes "fine" because fuck it, this day can't get any worse and maybe her stubborn baby brother will stop looking at her like she's the devil if he gets a hit in. Goka protests. Zanka throws herself at her—
—and hugs her so tight it squeezes the air half from her lungs. Kyouka is stunned. Goka is frozen in place, jaw hanging open. The entirety of the Red Horns Squad One watches in silent astonishment.
"I'm so glad you are okay," Zanka says, and his voice is soft and vulnerable and small and weak, like when he was a child, like when they loved each other. Kyouka is suddenly on the verge of tears, chocked with emotion. Still she's too shocked to return the hug, to hold him against her too, reassure herself on his steady breathing and rabbiting heart.
And then the minute is up and Zanka steps back swiftly, his expression wiped clean of emotion as he turns to Goka (still frozen in place) and in an entirely unaffected tone asks him if he can stay still for a minute.
Goka is sure Zanka is going to punch him because he was never as close to him as Kyouka, but he still nods, and a second later he has a chestful of baby brother hugging him. Goka cannot compute wtf is going on. Zanka tells him he was worried about him. Goka looks at his sister for instructions but Kyouka is too busy trying to control her suddenly spasming hands, trying to hold onto something (someone) who is not there anymore.
And then Goka's minute is up too and Zanka steps away, nods his head at them and thanks them for their time all businesslike. Then he's gone.
The memory of this exchange will haunt them all for months before any of them ever tries to reach out to the others and try to sort their shit out. But they will eventually!