Oh I like this. Maybe with the Red Grave City incident, governments will take demonic threat seriously and start their own guild of devil hunters. Also I'd like to see how governments handle the presence of demon. Will they annonce their existence publicly or will they try to hide them from the public ?
That could be an interesting take, especially with Nero. If government try to control demon hunters by imposing rules, how will Nero react ? For an exemple : imagine Nero accepted the proposition of being registered in a demon hunter guild. He sudently have to follow rules, which are at first not a problem and he agree with it. Until at one point, he is supposed to cooperate with others and works with other hunters. Everyone has a task to achieve, and Nero easily do his part. But then, one group get overwhelmed by demons. Nero wants to go help them, but the plan need him to stay where he is. Nero know he's far more powerfull then most hunters, and could go save the endangered group without compromising the mission, but is still held back by rules. That could be an interesting take on Nero.
Even for how the demon info are handled. Imagine Nero finally breaking out of the plan and saving the others, but then having the coordination of the team ruined because he didn't obeyed. The leader would hold a grudge on him, and try to manipulate informations to make him look like a threat. When he find out, Nero would burst out of rage and confront his leader about it. It would have consequences on Nero's life, like having his payment cut off. Nero would then have to decide between bending and following rules, but have no repercussions on his personal life, or just going out in solo, but face financial issues since the payment method have changed, and is now handled by government. And of course, he would start to think about a non legal approach with financial stability...
This would bend well in the begining of the story, right before the event launching the story forward (I don't have a name for that kind of event, my english is flawed :frown