The Maverick Hunters, known as Irregular Hunters (イレギュラーハンター Iregyurā Hantā?) in Japan, are an organization founded by Dr. Cain, dedicated to protecting the world at large from Maverick attacks. The main Maverick Hunter headquarters, stationed in Abel City, was featured in The Day of Σ, only to be destroyed near the end of the OVA.
- Signas (Commander post-X4)
- Dr. Cain (commander pre-X5, retired)
- Colonel Redips (Far East HQ commander, turned traitor)
- X (Unknown)
- Zero (Unknown)
Special 0 Unit (Shinobi)
Focuses on stealth combat and espionage
- Zero (Commander post-X2)
- Magna Centipede (Commander pre-X2)
- Blast Hornet (pre-X3)
- Web Spider (Retired pre-X4, joined Repliforce)
1st Mountain Region Unit
Oversees Maverick activity in rocky and mountainous terrain
2nd Jungle Region Unit
Oversees Maverick activity in rainforests
3rd Underground Unit
Oversees Maverick activity in places like mines or caverns
4th Overland Unit (Desert Post)
Overseas Maverick activity in dry and deserted areas
- Flame Mammoth (pre-X1)
5th Firearms Division
Specializes in the use of all types of firearms
- Axl (post-X7)
6th Marine Unit
Specializes in underwater combat and oversees Maverick activity in those regions
- Launch Octopus (pre-X1)
- Wheel Gator (pre-X2)
- Bubble Crab (pre-X2)
- Volt Kraken (pre-X5)
7th Air Cavalry
Specializes in aerial combat and patrols Maverick activity in the skies
- Storm Eagle (pre-X1)
- Overdrive Ostrich (pre-X2)
8th Armored Division
Compromised of heavily armored Reploids
- Armored Armadillo (pre-X1)
9th Special Forces (Ranger)
Compromised of highly trained commando Reploids
- Sting Chameleon (pre-X1)
10th Rider Division
Specializes in the use of Ride Armors and Ride Chasers
11th Medic Unit
Compromised of a team of Reploids specializing in first aid and advanced combat skills
12th Pole-arms Division
Specializes in the use of long-ranged combat using weapons such as spears
13th Polar Region Unit
Oversees Maverick activity in arctic regions
- Chill Penguin (pre-X1)
14th Grapple Combat Unit
Compromised of Reploids trained in the use of close-quarters combat and melee weapons
15th Mechaniloid Division
Uses Mechaniloids to help aid in combat
16th Intelligence Division
Specializes in gathering enemy intel as well as advanced combat
17th Elite Unit
Compromised of highly trained and skilled Reploids regardless of special abilities or talents
- Sigma (Commander pre-X1)
- Zero (Commander in X1)
- X (Commander post-X1-6, post-X7)
- Vile (pre-X1/The Day of Sigma)
- Chill Penguin (in The Day of Sigma)
- Storm Eagle (in The Day of Sigma)
- Boomerang Kuwanger (pre-X1)
- Spark Mandrill (pre-X1)
- Flame Stag (pre-X2)
- Gravity Beetle (pre-X3)
- Mac (X3, turned traitor)
- Double (X4, was a spy)
- Alia (post-X4)
- Pallette (post-X7)
- Layer (post-X7)
- "Navigator" (unnamed, Maverick Hunter X)
- Iris (Mega Man Xtreme 2 only)
- Lifesaver (Medical control officer) (post-X4 only)
- Douglas (Mechanic) (post-X4-X6)
- "Green Biker Dude" (pre-X2, deceased)
- Shadow (Command Mission, turned traitor)
- Depth Dragoon (Far East HQ)
Within the Maverick Hunters is a set group of rankings to determine not just how powerful a Hunter is, but also to determine how efficient they are. Mega Man X5 and Mega Man X6 are the first two games to give a Hunter Rank to the player, and shall be used here. Each game from Mega Man X5 to Mega Man X8 has different criteria for obtaining ranks depending of the player's performance. As ranks B, S and SA are the only ones mentioned in the story, it is unknown if some of the other ranks such as PA and UH are part of the Hunter's ranking or a gameplay extra.
- Rank E: Lowest rank in Mega Man X5.
- Rank D: Starting rank in Mega Man X6.
- Rank C: Scilla's starting rank.
- Rank B: Mega Man X's original rank, due to his hesitation for battle. This is his starting rank in Mega Man X5.
- Rank A: Scilla obtains this rank in Mega man X7. In X8, it was expanded upon where the player could gain "AA" and "AAA" rankings. "AAA" was the highest ranking for that game.
- Rank S: Only used in Mega Man X: Command Mission and featured in Mega Man X4, Cyber Peacock's stage, and the only rank mentioned in the game. Mega Man X, Zero, Axl, and Scilla all share this rank.
- Rank SA: SA is short for "Special A" (スペシャル?A also written as 特A級), and is Zero's current rank, as was Sigma and Vile's rank when they where still with the Maverick Hunters. In an alternate ending of Mega Man X5, Mega Man X obtains this rank and matches power with his fallen comrade Zero. This rank is associated with Mega Man X and Zero's two-time nemesis Dynamo, implying that he is strong enough to be compared with an Special A Class Maverick Hunter.
- Rank GA: Stands for "Gold A" (ゴールドA?). In Mega Man X6 this rank is obtained by collecting 1200 Nightmare Souls.
- Rank PA: Stands for "Platina A" (プラチナA?). Notoriously hard to get in Mega Man X5, but easy to get in Mega Man X6. (By collecting 5000 Nightmare Souls, easier to collect by "farming" them from Dynamo.)
- Rank MEH / MMH: The highest rank in Mega Man X5.
- Rank UH: Stands for "Ultimate Hunter" (アルティメットハンター?). The highest rank in Mega Man X6 and X7. In Mega Man X6, X and Zero can obtain this rank by collecting 9999 Nightmare Souls. This rank allows them to equip up to five parts (which is the maximum limit for each character).