The Maverick Hunters, known as Irregular Hunters 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)
- Zero (Commander post-X2)
- Magna Centipede (Commander pre-X2)
- Blast Hornet
- Web Spider (Retired pre-X4, joined Repliforce)
4th Overland Unit (Desert Post)
- Flame Mammoth
6th Marine Unit
- Launch Octopus
- Wheel Gator
- Bubble Crab
- Squid Adler (Retired pre-X5 due to the death of Launch Octopus)
7th Air Calvary
- Storm Eagle
- Overdrive Ostrich
8th Armored Division
- Armored Armadillo
9th Special Forces (Ranger)
- Sting Chameleon
13th Polar Region Unit
- Chill Penguin
14th Grapple Combat Unit
- Magma Dragoon
17th Elite Unit
- Sigma (Commander pre-X1)
- Zero (Commander in X1)
- X (Commander post-X1-6, post-X7)
- Chill Penguin (in The Day of Sigma)
- Storm Eagle (in The Day of Sigma)
- Boomer Kuwanger
- Spark Mandrill
- Flame Stag
- Gravity Beetle
- Axl (post-X7)
- Lifesaver (Medical control officer)
- Douglas (Mechanic)
- "Green Biker Dude"
- Shadow (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
- 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: This was expanded upon for Mega Man X8, 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, and Axl 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 were 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).