Commander Kido is a Dad, actually.
When Kido's first introduced, it's as this cold, distant leader who hates Neighbours and is running a strictly military operation.
But for someone who really hates Neighbours, he has a weird habit of taking in all these orphaned, homeless Neighbour kids. At first it appears like Yūma is the only exception, but then there's Hyuse, Yōtarō, his sister Ruka and Cronin.
There's other agents to think about too. There's a lot of characters in Border who, when you really think about it, would not normally be accepted into that kind of organisation. For example:
• Taichi; he's incredibly clumsy, which causes him to break or knock over all sorts of things - people included.
• Tsuji; he can't interact with women without having a mental breakdown, which is incredibly limiting on his ability to work with other agents.
• Nasu; outside of the trion body, she's disabled and it's mentioned that her health is ailing.
• Chika; despite her insane trion levels, she's incredibly inexperienced - having so much power yet not knowing how to wield it can be incredibly dangerous and destructive, it's a very high risk.
• Osamu; the exact opposite of Chika, his trion levels are so low he's outclassed by pretty much every other agent in Border.
• Kageura; he's incredibly easy to agitate and quick to respond with physical aggression.
• Hatohara; she cannot shoot people, no matter how hard she tries, and if Border was any other organisation they wouldn't have spared her a single thought.
All of these are characters who would normally be considered "problems" or "not worth it". But in Border, they're not only openly accepted, but given the environment and tools they need in order to properly grow and develop their talents.
If Kido only cared about killing the Neighbours, Border wouldn't be like this. It wouldn't be filled to the brim with a bunch of teenagers who, in one way or another, would be considered the "outcasts".
Kido is cold and distant because he's the commander, the very top of Border, and his job is to put Border first. He's the one who has to make the ultimate decision to sacrifice the one for the many, so he needs that emotional detachment. But that doesn't mean he doesn't care, or that he isn't invested in this hoard of teens he's in charge of.
This is a core part of his character, and we see it in the way he interacts with the main cast.
When Osamu is first brought before the Border Executives, he's in trouble for going against Border's rules on C-Rank trigger usage. But the reason he broke those rules was because people were in danger, and the nearest qualified Border patrol was miles away. He acted to protect people.
While the other directors discuss and argue these points, Kido sits silently and listens. He doesn't say anything until every side has spoken their piece and all variables are on the table. He lets Kinuta and Netsuki point out all the issues and flaws and he lets Shinoda defend Osamu's decision. He waits.
And then, when he does speak, he starts by acknowledging Shinoda's point about the benefits of Osamu's willingness to act. He acknowledges that yes, that is absolutely a good trait to have, especially in terms of being an agent of Border.
But Border comes first, and part of that is maintaining unity. He can't support an agent going rogue because, while it might be for the right reasons, it could cause serious complications in the future.
Yet even so, he gives Osamu one last chance to fall back in line. He gives him an easy opening for staying in Border.
Osamu could've said that no, he wouldn't do it again, and he might've been let off the hook. But he doesn't, because he's honest, and Kido sees that.
Then Jin interferes, and he provides a reason for Osamu to stay that directly benefits Border.
He agrees without hesitation. This way, Border is benefited and Osamu can still remain an agent. He doesn't need to choose between the one or the many anymore.
Then he learns that Osamu has contacted a Neighbour. Does he revoke Osamu's status as an agent? No. He doesn't even mention it, even though he literally just witnessed Osamu lie to a senior agent about his involvement with Neighbours.
What does he actually care about?
That there's an enemy running rogue in Mikado City. That the city and its civilians could be in danger.
Which leads us to how he reacts to Yūma.
Yūma is a Neighbour. That's all Kido knows about him at this point. Yūma is a Neighbour, the Neighbours hurt people and Border's job is to stop them. So Kido must ensure that this Neighbour doesn't hurt anyone either.
The very next thing he learns about the rogue Neighbour is that he has a black trigger. That whoever he is, he is twice as dangerous as a Neighbour is normally.
(Osamu, again, gets in trouble for withholding this information. And Kido, again, waits for everyone to say their piece about it before commenting - even though it would make more sense for him to punish Osamu on the spot.)
Jin suggests they make the Neighbour with the black trigger their ally.
There is merit to this, and Kido knows that - but he hasn't met Yūma like Osamu and Jin have, knows next to nothing about him except that he's one of their enemy and in possession of an incredibly dangerous weapon. So he chooses the good of the many.
Side note: at no point does Kido claim, or even imply, that Jin was wrong to believe they could make an alliance with the Neighbour. Kido recognises that Jin's suggestion is valid, it's just that his and Jin's priorities are different, so their decisions will ultimately be different as well.
Yet he still assigns Jin to catch the Neighbour, because Jin has Fujin - despite knowing full well that Jin is taking the opposite stance to him.
Kido isn't a fool. He is a very smart, perceptive man. He knows Jin's go-to tactic is abusing loopholes, the guy's whole shtick is literally bullshitting the rules. Which is why he's the least surprised when Jin pulls an Uno Reverse and claims he can't take the orders due to Border's chain of command.
Kido respects that Jin does not want to kill the Neighbour, and so he provides an opening for Jin to turn down the order without being disrespectful. In fact, Kido only becomes confused and surprised when Rindō changes the order. At no point does he take fault with any of the agents present.
The third thing Kido learns about the black-trigger-wielding rogue Neighbour is that he is, allegedly, Yugo Kuga's son.
Now, he has more to think about. There's more variables to consider. If it is Yugo's son, then Kido has just initiated a manhunt against the kin of his old friend. But at the same time, it's also possible that the Neighbour is lying.
So things have become more complicated, and you can see it in his expression.
To add to this, Yugo is now apparently dead. So the black-trigger-wielding rogue Neighbour is also, if he is to be believed, an orphan.
In the span of a few minutes, the situation has taken a nosedive into very delicate territory. Kido, as the commander, must make the ultimate choice. And as is his job, he chooses to put Border first.
What follows is a mad scuffle between the different factions of Border as Tamakoma aims protect Yūma while Kido aims to collect his black trigger.
Remember, Kido does not know that the trigger is what's keeping Yūma alive. At this point in the story, this is a fact that only Yūma himself knows until he shares it with Jin and Replica tells Osamu. So Kido's goal is not necessarily to harm him, it's just to retrieve the trigger. Likewise, the order he gives the A-Rank agents is "to secure the black trigger currently at the Tamakoma Branch" and "you must secure this black trigger by any means". He gives no order regarding Yūma specifically.
When this fails, the executives start infighting. The situation is rapidly deteriorating and things are getting out of hand, so Kido must be the commander again and force things back into order. And of course, he must make a choice: if he lets the black trigger go, the situation will calm back down, but then Tamakoma will have two black triggers and Border will be at a political disadvantage.
So he chooses what will result in the best outcome for Border over Tamakoma. He once again chooses to sacrifice the few for the many.
But then Jin swoops in and presents him with an alternative. He offers Fujin in exchange for Yūma's admittance as a Border agent and, after some arguing, reveals that his enlistment will be a direct benefit for Border later down the line. So not only will Border get Fujin, but letting Yūma join now will reward them with a net positive in the future.
And with minimal hesitation, Kido agrees.
After this, the tension dissipates and the dust settles. Things return to normal.
In chapter 41, Kido finally gets to meet Yūma fact to face. For the first time, he gets to see Yugo's son, the kid who caused so much drama and infighting just a few weeks ago. And what does he see?
He sees a well-meaning, genuine kid who doesn't hesitate to help. Which is why he doesn't lie when he promises Replica that Yūma will be protected under Border.
Plus, a minor but important detail here is that Replica only asked for Kido to guarantee Yūma's safety ("I would like the Border Commander to guarantee Yūma's safety in exchange for this information") yet Kido specifies that so long as Yūma is a part of Border, he will guarantee both his safety and his rights. He made the decision on his own to protect Yūma's freedom and independence.
