The Men-Fish were an amphibious race of creatures that fought Namor.

Paranormal government agency with the goal to eradicate all strangeness in the world.

The Men in Black is an organization that polices and monitors events which should remain unknown to the public. They work in secret, covering their tracks to make sure people do not know of their existence.

The Mephitisoids are a skunk-like alien race within the Shi'ar Empire. They are feared for their natural mind-controlling pheromone ability and forbidden from freely leaving their home planet.

Mercenaries, sometimes also known as a soldiers of fortune or hired guns, are a private individuals that join a military conflict for personal profit, are otherwise outsiders to the conflict, and are not a member of any other official military.

The Mercs are a mercenary team led by Deathtrap. They have fought Stormwatch on several occassions.

Deadpool's own team of mercenaries whom did 'heroic' work for the highest bidder.

Natives of Mercury.

Team made up of special forces bonded with the split up symbiotes from Hybrid.

An Aquatic species native to Maramere.

A group-mind that has sought to absorb the Earth into it's consciousness

In Tangent Universe, the opposite agency to Nightwing.

Mythical aquatic creatures with a female human torso and the tail of a fish.

The Mer-People are a reptilian amphibious race that dwell within the waters of The Savage Land.

Team of toons created by Arcade for his U.K. Murderworld.

A group of heroes who fight alongside Green Arrow to protect Star City.

Robin Hood's gang of thieves.

The watchers of their world.

A company experimenting with metagenes to sell designer superpowers

The Meta-Human Task Force is in charge of jailing and psi-scrubbing the brains of super criminals in an alternate universe.

Seven individuals come into contact with seven alien crystals that gave them their powers.

The Meta Legion is a superhero team operating in the New York area they are lead by Marine Omega and all reside in the same suburb. Their spouses network together to provide tactical support to the Legion and moral support to one another.

A metal band from San Francisco who have been together for over 30 years.

Five Women (Axe, Backbeat, Bongo, Brass, and Fusion) that merged into one giant robotic hero. Metallik was a member of the Team Titans.

A group of robotic superheroes created by William Magnus. Each of them are constructed with a responsometer, a device that gives them human intelligence and personalities and allows them to control their given element.

In the Tangent universe (earth 9), the Metal Men are a veterant squad of military specialists for dangerous missions in a world under a heated Cold War.

Dr. Will Magnus's creation of companions for the Metal Men.

A military affiliated superhero team from Earth-8. They are enemies to Lord Havok and the Extremists.

The Metropolis Police Department is currently led by Commissioner David Corporon.

Formed to combat and investigate metahuman crimes, the Metropolis SCU was originally headed by Maggie Sawyer and Dan Turpin and was a model for other SCUs in other cities.

MI: 13 is a government agency in the UK that deals with weird happenings throughout the country.

MI6 is the arm of the British Secret Intelligence Service concerned with international affairs.

Miagani, the bat-people, are a tribe that has guarded the bat cowl and belt for hundreds of years and respecting them as their god's symbols. They have developed senses and similarities with bats.

Basketball team.

Guardians of Justice. They have sworn their lives to protect all that need protection. They have been thought to have died out but the time has come for their return.

The Micronauts are a team of freedom fighters, explorers and adventurers. Originally dedicated to fighting the tyrant Baron Karza who enslaved most of their planets in the Microverse, the team has stayed together after his defeat, exploring the Microverse.