If Heiji and Kazuha end up working together as police, my headcannon is that they're the "private but not secret" couple.
Like, this newbie who just transferred heard that they were childhood friends, which would explain the bantering and arguments.
But during actual work, they're absolute professionals. And they make a great team. Heiji's sharp deductions, Kazuha's keen senses. Them bouncing off ideas together during discussions.
And they work great with everyone in the department as well. Great team players.
Kazuha is sweet and charming with everyone.
Heiji is charismatic and always surrounded by other people.
And this newbie themselves get along well with both of them, even if they've only been here for a week.
So imagine their surprise, as the team rescued Heiji who was captured by a criminal after a scouting mission gone wrong, Kazuha immediately jumped into his arms and hugged him tight after making sure he was fine.
And their surprise doubled to see Heiji hugging her back.
The newbie didn't realise they were staring until another colleague said "Oh? You didn't realise they're dating?"
The colleague laughed. "It's subtle, but you'll notice the signs after this"
Him getting her a drink during late night shifts.
Her passing him a pen just as he realised he needed one.
One waiting for the other to finish up their paperwork before heading back home together.
How they unconsciously moved closer to each other during discussions.
It was actually endearing.
But the newbie nearly spilled their coffee when they discovered who Heiji's and Kazuha's fathers are.
