make it an investigation agency only instead of a full blown paramilitary agency, and not as big and tentacular as the AODU (which for the moment is basically NERV Japan with magic, which is just overkill compared to the other factions) but as a bureau of investigation specialized on the occult, composed of inspectors with particular profiles (a la Mulder), or who had an experience with the occult during their service (such as an inspector that ended in a Witch barrier while trying to save someone and avoided being brainwashed by a passing MG or Incubator), and who want to investigate and discover more about the occult world as a whole, and to protect the citizen as discreetly as possible (to avoid knowledge about magic to spread, seeing its near limitless possibilities, and also to avoid mass panic and the return of old witch pyre from the old days of the inquisition)
To give you a point of comparison, if you're familiar with the videogame
Parasite Eve 2, the heroine works for a special branch of the FBI called the MIST (Mitochondrial Investigation and Suppression Team), charged to investigate and deal with cases that could implicate mutant created by the mutation of part of living beings cells (the famous Mitochondria), all their operatives are first and foremost inspectors, but received extensive training to deal with the weird shit that would attack them in their line of work.
The AODU would be the same thing : a special bureau affected to the Prefectural Police Headquarter of Osaka. Of course, they hide their true purpose to their colleges of the police, officially they are a division specialized on international traffics (for why "international" I'll come back to it later), but still they aren't very liked of the rest of the police force due to their secretive nature and all the weirdos and gaijins composing their ranks.
Now about the "international" part of their cover, my idea was to make the AODU more resourceful and a true potential menace for the MG gangs, and so people wanting to RP these guys wouldn't be limited to Japanese character, and is actually as a division of Interpol specialized on the occult.
In short : Interpol has a secrete division specialized on the occult, which has a branch in every countries' Law Enforcement Headquarter, which in turn administers all the bureau present in the local police forces.
For Japan, which is the country that interest us, the Japanese Branch of the AODU has its HQ in the offices of the National Police Agency (in Tokyo I think), and administers the local bureau across the country, one for each of the 47 Prefectural Police Departments, the bureau of Osaka being the one we'll deal with.
Maybe you noticed that I talk about magic as a general term, and that's on purpose : Incubators have the means to let girls access to magic by extracting their soul and putting it in a physical form, but what tell us that they are the only ones who discovered how to use magic? After all, history is filled with priest, druids, oracles, shamans, some of then must have found a way to use the power of their soul to use magic!
So the AODU counts with some magic users in their ranks to help in their investigations and dealing with magical threat. You have a little of everything : voodoo, white magic, shamanism, occultism... which are all different mediums to access the magic potential inside one's soul, in short the principle behind the powers is the same for everyone (using the power of the soul) but the package and look of the powers will differ.
I can see your concerns from here : I'm turning it into
Vampire : The Masquerade or other White Wolf game where everyone and its mother have magical powers able to turn you inside-out or incinerate you or mentally control you or invoke some demons!
To balance everything, their use of magic is very limited compared to MG : magic powers granted by Incubator wishes are
the big shit, a level of exploitation and weaponization of magic absolutely unseen and impossible to copy or replicate. The magic accessible to the AODU are much more passive and weak than with MG, essentially turned toward helping in the investigations : the ability to see what's normally invisible to humans (such as the borders of a Witch barrier, Witches without a barrier, the best of them being even able to see the Incubators if they concentrate enough), sense the use of magic (two MG fighting each other, an contract being made, a transformed MG if the operative is close enough), detect great amount of grief (Witch, Familiar, MG about to witch out, victim of a Witch Kiss) although to a much lesser degree than a soul gem which is pretty much a radar for magic and grief... even their more active abilities are turned to support, such as the ability to remove the Witch Kiss from a victim to turn it back to normal, and use the "magic signature" from the Kiss to help track down the Witch, some of the AODU "mages" even have some powers that can temporarily calm down a Witch and subdue them the time to extract the victims from the barrier and call in reinforcement : operative
won't fight a Witch unless they don't have any other choice, it's too dangerous to do it alone or even with a teammate, just the Familiars would be a great danger (imagine two humans with simple pistols against all of Gertrud or Charlotte's Familiars, which counts in the dozen), they'll take the civilian, get out and call specialized units with heavy armors and weapons to take care of it, a "anti-magic SWAT" of sort.
At best, the AODU "mages" can conjure some telekinetic push or a few pyrotechnic tricks as self-defense techniques, but nothing more. Again with the
Parasite Eva 2, Aya and her powers would be considered a top tier mage, the big shots that only are a dozen in the whole AODU, meaning that unless a Walpurgisnatch appear in Osaka, the local Branch won't employ one, but that give you an idea of what their best mage operative can do. And even then her chance to win against a MG on a direct confrontation aren't that good.
Now even if in a direct confrontation against a MG or a Witch they are in a severe disadvantage, that doesn't mean that they are completely hopeless : on top of their training and weapons, they some artifacts that help them in their job : a standard equipment is to have an anti-magic amulet inside their police badge that grant them a resistance to magical phenomenon : for example a MG or Incubator can't screw with their mind (like Kyubey did to Madoka in episode 11), they're immune to Witch Kisses (in exchange it hurts like a bitch!) and some magic powers have a reduced impact on them (example : Mami's ribbons won't be indestructible and with some forcing and a useful hidden knife, they can eventually cut them), as long as they have their badge on them of course. They also have a couple of amulets or crystals for emergency situations (example, a crystal that generate a one-time shock wave around them when they break it, useful when a bunch of familiars are about to gang on you), and more importantly, they know the way to generate "anti-magic" fields : by painting sigils on the ground and walls connected by a crystal, or amulets with an area of effect, your choice, they can secure an area where at best the magic will be disturbed and the MG will have her powers weakened, an anti-magic area of greater level (needing more time to prepare and more crystals) will "de-transform" them, making them unable to transform back and thus blocking their powers, they keep their augmented strength and speed due to the fact they are liches, but even then they are put against armed and well trained adults, at which point the tables dramatically turns against the MG.
The highest level anti-magic field even perturbs the soul gem control ever the body, reducing her strength and speed to the level of a normal person of her physical age, but these fields are very complicated and require a constant supply of energy, so they are only found in the AODU cells to contain especially dangerous MGs.
My idea was to play a duo of inspectors composed of a young European inspector without powers recently assigned to Osaka, who's well spoken and able to easily extract information from people and happened to fall into a Witch barrier during an investigation about disappearances in series and then hired by the AODU, accompanied by a middle-aged Haitian Houngan (male
Haitian Vodou priest) able to "purify the corrupted" (erase a Witch Kiss), "speak to the spirits and the dead" (it's left ambiguous if he really talks to spirits, but whatever he does helps him gather information from recently deceased corpses to know what happened to them, as well as track Witches) and also "see what's not here, as well as the White Devil" (see Witches out of their barriers, the edge of barriers, the "White Devil" being of course the Incubators), the guy as seen some
serious shit during his life, had to cure enraged victims of Witch Kisses, fight against Familiars and "calm" Witches, he saw how the "White Devils" had a part in the trouble in 2004 that led to the coup d'etat, and later exploited the despair born from the 2010 earthquake to contract even more girls, which make him hate them with a passion equaled by few members of the AODU. Still, he managed to keep a positive view of life, seeing the AODU gaining power as a hope that they can fight the "White Devils" everywhere in the world.
He knows that their true names is Incubator, and in his reports he design them as such, but when speaking about them he insist on calling them "White Devils" to clearly signify his hatred of them, no one in the AODU disagree with him.
I want to avoid the cliché of the "exotic" priest completely nuts and sprouting nonsense or highly cryptic phrases : the guy can lapse into philosophic musings and life lessons (he's a priest after all), but most of the time is very to-the-point (can even seems to be rude some times), although it happened that he got into full-blown cryptic and pseudo-philosophical ramblings... just to troll and annoy his teammate! ("... what you said didn't actually had any sense right?" "Maybe." "For God sake, I hate it when you do that!" "Oh come on, leave an old man his fun from time to time!" "You're 43, that's hardly being an old man" "In my country it is."), he has a very special brand of humor, very black, sometimes bordering on gallows humor, and is also an incorrigible deadpan snarker, still his experience and hindsight are very valuated among the AODU, and he's respected due to his extensive knowledge about magic and nerves of steel. He's the "sempai" to the European "kohai", helping him to adapt to his new job and this world of magic he never suspected before.
Until recently, the AODU was the inside-joke of the higher echelons of Interpol, never taken very seriously due to all the skepticism surrounding the true danger of magic in our modern world where only a few people believes in it anymore. But everything changed when the record of the almost WS-level Witch was made, interpol realized that magic can be a very dangerous thing if left unchecked, resulting in massive funds being dumped in the AODU which increased in size and strength, for Japan for example it passed from having only a couple of bureau in the Tokyo and Osaka prefectures with a few agents each to have a bureau in each of the 47 Prefectures with personnel ranging from a small team for the less populated Prefectures a good dozen of agents for the more densely populated areas (hello Osaka).
Before they were a joke barely worthy of the Incubators attention, with barely the power to really investigate their MG contracting business, now they are powerful, everywhere, well equipped and you don't fuck with them, forcing the Incubators to slightly revise their strategy and advice the MG to keep a lower profile to not attract the attention of their investigation teams.
To resume, what the AODU lacks on brute strength and raw magical power, they compensate by high training, composure (they're adult against teenagers), preparation, specialized equipment and magic, and more importantly in their social position : they're cops, so they can go anywhere, interrogate anyone they want, can require the collaboration of any citizen or organization, and can make a MG hiding her secret to her family nigh impossible.
They will be a lurking menace, investigating strange events usually long after the MG left (example : Hitomi and the other people kissed by the Witch in episode 4 and woke up in the middle of the abandoned warehouse without any recollection of how they ended here), as long as the MG are prudent and keep a low profile, everything will be okay, but if their inspectors start to investigate on you, you're in big problems, because they'll question your friends, teachers parents, neighbors, forcing the MG to stay in a
very low profile (no Witch hunts, no training on magic, staying far from MG rallying points such as Iibey's "Brick House Drinks and Sundries" stores) until they find nothing for long enough to drop the investigation, which is of course very problematic to find Grief Seeds, better have some MG friends that can do the hunt for you and discreetly bring you the GS at school.
A pro-tip is to hide the blatant signs of being a MG, by changing the contract ring by another jewel (earing, bracelet...) and use nail polish to hide the fingernail marking.
If they identified your character as a MG, you're pretty much fucked : they'll ask you to follow them for a couple of question or your implication in a case of whatever, if you fly away they'll declare you missing child or suspect, at which point all the police of the country will look for you, Iibey will abandon you because you "broke the Masquerade", most of your friends will be put under surveillance in case you try to contact them.
Girls who ended in this situation either fell in despair and witched out, became loner on the run (some left the country), committed suicide, or joined Myaabey's gang.
Now what does the AODU with captured MG? They don't kill them, they bring them in custody, interrogate them about the magic world (MG, Witches, Incubators...), and study their magic to find a way to reverse the contract, put back their soul inside their body and let them have a normal life (or arrest them if they are insane and committed crimes).
Yes, ladies and gentlemen, they are the good guys : they want to protect the innocent people and see most MG as victims of these mysterious supernatural beings know as Incubators. The problem for the MG is that firstly, they don't have any single clue of how the process of extracting the soul and put it in a solid form, works so reverse-engineering them is a pipe dream and will stay that way for many years, and secondly the Incubators will try their best to kill the MG to keep the AODU from discovering new things : the more they learn, the more complicated the energy harvesting system will be for them, their worst case scenario is that the AODU discover a way to detect all the Incubators and combine it with satellites, and a way to revert the contract, such scenario already happened in other worlds and completely fucked the Incubators business; forcing them to abandon these worlds, and mankind is a very strong and profitable source of emotions and thus energy, so the Incubators really don't want to lost it!
Myaabey will rather try to make the MG escape, but she refuses to follow him, because she was convinced by the AODU to stay, he'll make her assassinated too.
But you'll ask : don't Myaabey and the AODU's have similar objectives, why would they work together? Well, there are a few key differences : first, Myaabey is insane and very paranoid and mistrustful of the AODU, he fears that even though the AODU have genuine concern for the MG, the governments will sooner or later use what they are learning to mass weaponize magic and create their own army of Magical Girls and Boys, making the situation worse for his protégés, the second and more important one is that while the AODU want the end of the MGs (because teenage girls shouldn't have to fight dammit!), the girls of Myaabey's gang only want to the of the MG system, ie being manipulated by the others Incubators, they're actually very happy with having nigh unkillable bodies and lots of super powers!