Origin

Inexplicably, a mountain suddenly appears in Los Angeles, triggering a massive earthquake. During this event, Ghost Rider happened to pass through town, as Morbius was attempting to feed off Werewolf by Night's blood, and Man-Thing had an encounter with a fisherman. The simultaneous appearance of the mountain and a mystical being named Starseed brings the four together.

Encountering Starseed, Werewolf by Night, Morbius, and Man-Thing try to attack him but Ghost Rider intervenes, protecting him. The attack on Starseed, however, is fatal, and prior to his death, reverts the four back to their original human forms for a split-second.

After this revelation of their human selves, the four realize they have a connection; sympathizing with each others' situation, but soon depart and go their separate ways.

Creation

The Legion of Monsters was created by Bill Mantlo and Frank Robbins in 1976 and first appeared in Marvel Premiere # 28.

Aftermath

Each character would soon meet each other temporarily during various occasions. Ghost Rider and Morbius would team up as members of the Midnight Sons. Morbius and Werewolf-by-Night would also encounter each other several times, and Werewolf-by-Night would engage in a battle against Man-Thing.

Ghost Rider, Werewolf-by-Night, and Morbius, end up getting killed by Switchblade. However, they are resurrected, and the group gathers again, at least in terms of an appearance in a newspaper photograph; in the "House of the Spirits of Vengeance" series featuring Ghost Rider.

The Return of the Legion of Monsters:

Minus Ghost Rider, a new Legion of Monsters team forms, and incarnation features Morbius. Werewolf-by-Night, Man-Thing, including new members the Living Mummy and Manphibian. Their vow is to protect monsters and creatures that have been targeted for extermination.

The Legion soon encounters some surviving monsters from a Japanese free-for-all kill. The Legion sends them into the Morlock Tunnels. It is here where they start a type of Monster Metropolis, where the monsters and creatures can live in peace.

Recently, the monsters encounter and save the Punisher, after he was seemingly killed after having his body eviscerated, mutilated and torn to shreds by Daken. Punisher was resurrected as "Frankencastle", with a Frankenstein's creature like appearance, and his body pieced and sewn together with various different parts. Morbius wants Punisher to help lead the group because of his military experience and us it to help the Legion as well as the other monsters against the Japanese monster hunters lead by an ancient monster hunter named Hellsgaard. they attack the tunnels and capture Manphibian and Morbius who is holding the powerful blood stone.

The rest of the Legion kill most of the enemy soldiers with the help of the new Punisher and Giganto.

The Punisher later attacks Hellsgaard who is now powered by the Bloodstone and then kills Manphibian by shooting him in the head. Punisher and Hellsgaard end up fighting in Limbo. The result of the fight, Punisher gets mortally wounded and Manphibian turns out to be allve and defeats Hellsgaard by ripping out of his weaponized suit. The Legion leaves Hellsgaard to live the rest of his life suffering in Limbo.

Later on The Legion of Monsters go to Monster Island to retrieve the Bloodstone from The Punisher who is using it to not only heal him but as a source of power fueled by revenge which is making him extremely dangerous. The team with the help of Elsa Bloodstone. But Bloodstone gets out of hand and puts the Legion of Monsters in danger. Punisher almost kills Elsa but is stopped by Living Mummy convincing him the the stone is ruining his perception of who truly deserves to die. Punisher gives the stone back the the Legion of Monsters and leaves them.

In Haunted Hulk the Legion assisted in removing the Dark Samson poltergeist that was haunting the Red Hulk.

In Other Media

Video Games

Marvel Vs. Capcom 3

The Legion of Monsters make a cameo in Marvel vs Capcom 3 during Jill Valentine's character ending. They are seen ambushing Blade and Jill forcing the two to team up.