So the Devil Hunter Corps is a branch of, as the name suggests, people who've enlisted to hunt down Demons in foreign and domestic locations. I'm not gonna sugarcoat it, this was inspired by Chainsaw Man. This won't be like the Centurion Corps thing; it's just an outline for this branch and stuff for whenever I actually use it, and you can refer to this book for things.

There are 3 types of mages:
Telekinesis or Flux Mages, whose magic lets them manipulate objects. Examples include Healing (by moving the body to heal fast), Ballistics (by moving the bullets to the desired location), and Heracles (increases physical strength with magic).

Perception or Insight Mages, whose magic lets them see what's going on around them beyond normal human scope. Examples include Three-Dimensional Comprehension (perceive where all targets around you are), Magic Eye (view and discern objects incredibly far away), and Photographic Memorization (remember things in extremely vivid detail).

Attack or Combat Mages, whose magic transforms energy into a means of directly attacking an enemy. Examples include Sturm (manipulates gusts of wind), Thunder (manipulates electricity), and Sunlight (manipulates light and heat)

All Devil Hunters wear a simple uniform consisting of a white long-sleeved uniform shirt, black uniform pants or a skirt, a black tie, black footwear, and a black beret. Those who are Telekinetic Mages wear a blue shoulder cord, those who are Attack Mages wear a yellow shoulder cord, those who are Perception Mages wear a green shoulder cord, and those who are Hunters wear a silver shoulder cord on their left shoulder. Some Warlocks are allowed to wear 2 shoulder cords if permitted by their command. The beret of a soldier is decorated by their regimental insignia, not unlike the American flashes or British cap badges.

In some cases, a Hunter may show a latent talent for magic. They're trained to use it and are referred to as Warlocks. A Warlock (Witch if they're a female) is denoted by a bichromatic shoulder cord depending on what type of Mage they are: silver and blue for a Telekinetic Warlock, silver and yellow for an Attack Warlock, and silver and green for a Perception Warlock.

Edit
So I'm restructuring this after talking to some friends of mine. The Hunters are now humans who've been altered by surgeries and chemical augmentations to be supersoldiers as advanced Infantry. Those who have made a pact with Demons/Devils or become a Cambion are called Slayers, and they're fewer in number, with 60 Slayers per company and 4 companies per Battalion. Slayers have red shoulder cords. 

Ranks
Due to the small numbers, the Devil Hunter Corps uses both enlisted and officer ranks as part of their structure. All soldiers, Sergeant and above, are referred to by rank rather than sir. In some cases, lower-ranking soldiers may substitute the title and surname for sir for convenience, such as if the soldier in question has a long or hard-to-pronounce surname. Because of how they're designed, rank insignia can go on the lapels as pins for easy identification or on the shoulders as epaulettes.

Cadet, Private, and Corporal are your normal junior enlisted. They are under the sergeants in a platoon, who act as squad leaders.

The 2nd Lieutenant is the head of any Devil Hunter platoon, and they report directly to the 1st Lieutenant, or regular Lieutenant, as on paper. A normal Lieutenant advises the Captain, who is the commander of the entire company.

Cadet, Private, and Corporal are your normal junior enlisted. They are under the Sergeants in a platoon, who act as squad leaders.

The 2nd Lieutenant is the head of any Devil Hunter platoon, and they report directly to the 1st Lieutenant, or regular Lieutenant, as on paper. A normal Lieutenant advises the Captain, who is the commander of the entire company.

The Colonel is the commander of an entire Battalion, consisting of 6 Companies. The Major is the advisor to a Colonel and has Captains directly report to them.

The Brigadier is often the sole commander of an entire Devil Hunter Brigade, consisting of 6 Battalions. In rare cases, a Brigadier can be advised by a Colonel whom they promote to an executive officer while finding another Major to replace that Colonel. They're often called a Commodore and have a small skull over their Brimmstone cross.

The General is often the sole commander of an entire Devil Hunter Regiment, consisting of 6 Brigades. As there are only 15 throughout the entire branch, they are often on the cabinet of defense for the country. Similar to a Commodore, a General can promote a Brigadier to act as their advisor and go through the chain of command to fix the structure as needed. The promoted Brigadier is often called a Marshal and still has a skull over their Colonel rank insignia's Brimmstone cross

There does exist a rank above the general, and it's the hardest to obtain. The highest rank is called Magister, and their insignia is the Roman Aquila with 2 heads and a bundle of arrows. The Magister is the sole head of the Devil Hunter Corps and is often the strongest. Many soldiers can go their entire service careers and see the Magister only once, and that's at a ceremony. 

Units
(Note the symbols under each name are the symbol that goes on their berets)
Homestation Command
- Homestation Command describes the 5 regiments that operate within national borders. 

1st Devil Hunter Mage Regiment - Iron Crosses

The oldest and most decorated regiment, making heavy use of Attack Mages. They act as the golden standard for the branch, though Hunters tend to say otherwise.

1st Attack Mage Brigade

2nd Attack Mage Brigade

3rd Attack Mage Brigade

4th Attack Mage Brigade

4th Telekinetic Support Brigade

1st Perception Recon Brigade

66-97th Slayer Battalion

2nd Telekinetic Regiment - Black Lances

A regiment that makes use of Hunters supported by Telekinetic mages using weapons known as Lances to pierce through Devils with heavy armor or formations. They're highly aggressive for a primarily telekinetic regiment

1st Telekinetic Mage Brigade

2nd Telekinetic Mage Brigade

3rd Telekinetic Mage Brigade

2nd Hunter Mage Brigade

6th Hunter Brigade

4th Hunter Brigade

99-76th Slayer Battalion

3rd Perception Recon Regiment - Ghost Hounds

A regiment comprised of a majority of Perception Mages who perform reconnaissance and scouting for other units. They are always attached to other frontline units for intelligence and support, be it direct or sustainment.

2nd Perception Mage Brigade

3rd Perception Mage Brigade

4th Perception Mage Brigade

5th Perception Mage Brigade

3rd Hunter Brigade

5th Telekinetic Brigade

81-85th Slayer Battalion

4th Telekinetic Artillery Regiment - Ash Guard

A defensive regiment stationed on the borders to prevent Devil invasions with Telekinetic mages and artillery. They're always stationed directly on borders close to towns that they have been known to turn into a fortress at a moment's notice.

6th Telekinetic Artillery Brigade (155mm)

7th Telekinetic Artillery Brigade (155mm)

9th Telekinetic Artillery Brigade (120 and 80mm)

10th Telekinetic Artillery Brigade (800mm) (Yes, this was an actual artillery caliber used in WW1. They just have this.)

5th Hunter Brigade

8th Perception Mage Brigade

41-80th Slayer Battalion

5th Devil Hunter Regiment - Red Scars

A unit of almost all Devil Hunters feared for their tactics and pragmatism. They're feared by both Devil and soldiers alike and feature the first mixed mage brigade, as well as commonly attach soldiers to other units for training.

1st Hunter Brigade

2nd Hunter Brigade

4th Hunter Brigade

6th Hunter Brigade

7th Hunter Brigade

1st Mixed Combat Mage Brigade 

15-91st Slayer Battalion

Overseas and Expeditionary Command
- O&E Command describes the 5 regiments that are often sent outside of national borders to work with foreign law enforcement and military to kill Devils.  

6th Expeditionary Regiment - Crimson Banners

A balanced regiment of multiple Mage and Hunter battalions known for carrying red banners everywhere they go.

5th Attack Mage Brigade

8th Attack Mage Brigade

18th Perception Mage Brigade

15th Telekinetic Mage Brigade

11th Telekinetic Mage Brigade

8th Hunter Brigade

40-69th Slayer Battalion

7th Combined Mage Regiment - Storm Riders

A rapid response regiment comprised of Telekinetic and Attack mages for lightning-fast assaults. They're one of the only Regiments that actively use vehicles for mobility tactics.

7th Attack Air Assault Brigade

9th Attack Armored Brigade

12th Attack Mage Brigade

12th Telekinetic Helicopter Brigade

14th Telekinetic Mage Brigade

7th Perception Mage Brigade

20-93rd Slayer Battalion

8th Perception Regiment - Night Watchers

A regiment of majority Perception mages who monitor foreign borders as a reconnaissance unit for other regiments and allied units nearby

14th Perception Cyberwar Brigade

12th Perception Counter-intelligence Brigade

11th Perception Recon Brigade

11th Perception Mage Brigade

19th Attack Mage Brigade

12th Hunter Brigade

74-37th Slayer Battalion

9th Disaster Relief Regiment - Garden Snakes

A regiment that specializes in the containment and capture of Devils. Primarily comprised of Telekinesis mages

22nd Telekinetic Mage Brigade

20th Telekinetic Mage Brigade

21st Telekinetic Mage Brigade

23rd Telekinetic Mage Brigade

20th Perception Mage Brigade

16th Hunter Brigade

45-59th Slayer Battalion

10th Attack Mage Regiment - White Flames

A regiment of primarily attack mages who use flame-based magic and heavy ordnance. They also house Chaplains within their units not in service to the Devil Hunter Corps

11th Attack Artillery Brigade

14th Attack Artillery Brigade

15th Attack Armored Brigade

16th Attack Mage Brigade

17th Attack Mage Brigade

14th Hunter Brigade

18-93rd Slayer Battalion

Specialist Command
- Specialist Command describes units trained in specialized kinds of warfare. They also fall under both Homestation and O&E command and are deployed more often than the others. 

11th Hunter Regiment - Howling Wolves

A Hunter regiment of relentless shock troops, famed for taking on locations ruined by Devils

11th Hunter Brigade

17th Hunter Brigade

18th Hunter Brigade

20th Hunter Brigade

21st Hunter Brigade

17th Telekinetic Support Brigade

36-82nd Slayer Battalion

12th Recon Regiment - Glass Eyes

A specialist Perception Regiment that specializes in intelligence, counter-intelligence, surveillance, and reconnaissance against Devils

15th Perception Cyberwar Brigade

16th Perception Counter-Intelligence Brigade

17th Perception Recon Brigade

19th Perception Mage Brigade

16th Telekinetic Ordnance Brigade

10th Hunter Brigade

77-37th Slayer Battalion

13th Regiment - Death 13

A regiment that specializes in multiple kinds of combat, from disaster relief to shock assault. They're seen as the elites that travel from base to base, especially their Hunters

13th Attack Mage Brigade

6th Attack Mage Brigade

13th Perception Mage Brigade

13th Telekinetic Mage Brigade

18th Telekinetic Support Brigade

13th Hunter Brigade

42-13th Slayer Battalion

14th Covert Regiment - Night Stalkers

A regiment of hunters assigned into smaller kill squads supported by mages of all kinds

19th Hunter Brigade

22nd Hunter Brigade

23rd Hunter Brigade

2nd Combined Mage Brigade

3rd Combined Mage Brigade

6th Perception Mage Brigade

58-50th Slayer Battalion

15th Heavy Assault Regiment - Iron Hammers

A combined arms regiment that utilizes Attack and Telekinetic mages in addition to artillery and sapper tactics

10th Attack Sapper Brigade

20th Attack Mage Brigade

19th Attack Mage Brigade

21st Attack Engineer Brigade

21st Telekinetic Artillery Brigade

19th Telekinetic Mage Brigade

50-33rd Slayer Battalion