In the Marvel Universe, there is a part of it that remains the realm of the supernatural. This part goes back millennia to an age where magic ran wild and extradimensional beings known as demons preyed on the earliest forms of humanity. As time moved forward, these demons found their power waning on Earth and almost all of them fled to other dimensions.

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In the present day, many of these demons have tried to return to Earth but were met with resistance from various heroes including the Sorceror Supreme. Some have tried to bind themselves to this dimension by using humans as hosts or breeding with them to create links to the dimension. Some heroes have even managed to serve humanity by controlling demons, which can be a deadly prospect since there are very powerful demons in the Marvel Universe.

10 D'Spayre Preys On Human Fear & Sadness

The demon D'Spayre feeds on human despair

D'Spayre was created when the Dweller in Darkness coalesced the collected fear of Atlantis and Lemuria sinking. When he first appeared, it was in the Nexus of All Realities, guarded by the Man-Thing. When he was defeated by Man-Thing and Spider-Man, he moved to more subtle methods.

He began to prey on lonely humans, driving them into despair. It's believed that he feeds on these emotions, but he takes pleasure in torturing his victims. He's crossed paths with several heroes on Earth, including the teams of Cloak and Dagger and the X-Men.

9 N'astirh Orchestrated Inferno

N'astirh the demon attacking the X-Men

N'astirh came to the forefront, manipulating Madelyne Pryor, the mutant clone of Jean Grey, to launch the demonic invasion that was called Inferno. N'Astirh also manipulated Magik to open a portal to allow the demons from Limbo to invade New York. He proved himself to be sinisterly intelligent, infecting himself with the techno-organic virus to become a sentient, demonic, magical computer.

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N'astirh became a formidable foe, thwarting attempts to destroy him. His techno-organic nature was used against him, as the X-Men and X-Factor used extreme temperature changes and a massive bolt of lightning to destroy the demon. He was later resurrected and tried to manipulate the X-Men to kill Magik.

8 Zarathos Thwarted Other Demons As Ghost Rider

ghost rider from Avengers #22

The Demon Zarathos is known to comic fans as the source of Ghost Rider's power. He was a demon that corrupted the Spirits of Vengeance and futilely challenged Mephisto. Mephisto would periodically bond Zarathos to a mortal as a parody of the Spirits of Vengeance. This practice brought Zarathos into contact with Johnny Blaze as the demonic hero Ghost Rider.

Blaze eventually found himself fighting for control with Zarathos until he was able to trap the demon in a soul-crystal. Zarathos was freed by Lilith and he collaborated with her to take over the Earth. During their defeat, Zarathos was destroyed.

7 Blackheart Got in the Way Of Mephisto's Plans

Blackheart fighting Miles Morales and Peter Parker

Blackheart was created by Mephisto as a "son" using the collected evil of centuries of murder in a New York town. Blackheart faced numerous heroes before Mephisto began to restrict his powers to teach the young demon humility. Blackheart instead began to try and overthrow Mephisto using various mortals.

Blackheart's efforts were often met by Ghost Rider, no matter who possessed the Spirit of Vengeance. He's continued to threaten Mephisto's power and rule. Most recently, he got in the way of Mephisto's plans for Miles Morales, so the elder demon dragged his son home.

6 Null, the Living Darkness Took Over Earth

cover detail from Defenders #114

Null the Living Darkness first came to the attention of the Defenders when he attempted to take over a Virginia town. Then he was stopped from using a pawn by Ghost Rider. The Null went to the Earth of the Squadron Supreme where he merged with the Over-Mind to take over the world and threaten that entire universe.

The Defenders and the Squadron uncovered Null's role and confronted him, almost futilely. A group of psychics merged the psionic power of the two teams before using the latent goodness inside Null. It had laid there since he formed from the collective negative impulses of an angelic, alien race. Null was destroyed and has not been seen since.

5 Dormammu Always Comes Back To Threaten Earth

Dormammu hulks out in Marvel Comics

Dormammu was one of the first extradimensional threats that Doctor Strange faced. He had conquered the Dark Dimension and enslaved the Mindless Ones. When he tried to conquer the Earth dimension in the present day, he was thwarted by the Sorceror Supreme's disciple, Doctor Strange. For this, Dormammu swore vengeance against Strange.

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Dormammu returned to threaten Earth again and again, with Strange often defeating him with allies like the Avengers and Defenders. Strange even aided the resistance in the Dark Dimension against Dormammu's rule, aiding in deposing him.

4 Shuma-Gorath Takes Armies Of Heroes To Stop Him

Alex Ross rendered image of Shuma-Gorath

Shuma-Gorath had already conquered multiple dimensions when he came to Earth millions of years ago. He was banished by a time-traveling sorcerer. He returned and was buried in a mountain by the god Crom before an escape ended with Shuma-Gorath banished to another dimension.

In the present day, Doctor Strange began a wave of heroes standing in the way of Shuma-Gorath returning to Earth's dimension to conquer it. Often, he has taken advantage of unrelated events weakening or opening a portal between dimensions.

3 Chthon Possesses Only The Most Powerful

Origin of Chthon in Marvel Comics

The Elder God Chthon bound much of his power in the magical tome known as the Darkhold. This gives him a path to return and gather the souls of those using the Darkhold. One of the first vessels that he prepared upon her birth was Wanda Maximoff, also known as the extremely powerful mutant the Scarlet Witch.

Chthon continued to use his link to the Darkhold attempting to escape his dimension. He had impregnated the wife of a priest charged to protect against Chthon. He possessed Wanda's brother, Quicksilver and during Hydra's "Secret Empire", once again possessed the Scarlet Witch. Many times, he finds himself stopped by Doctor Strange.

2 Mephisto

Mephisto unleashed

Mephisto is for all intents and purposes, the Marvel Universe's devil. He's constantly bargained for souls and calls his domain Hell to exploit humanity's fears of the biblical Satan. He doesn't limit himself to Earth, manipulating and collecting extraterrestrials as well. It was his kidnapping of the Silver Surfer's lost love Shalla Bal that was one of his first chronicled deeds.

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He's crossed paths with almost every Marvel hero. He bonded Zarathos to Johnny Blaze and created the hero Ghost Rider. He's eliminated the children of Scarlet Witch and the Vision as they were parts of his power. He struck a deal with Spider-Man to claim the love he had with Mary Jane Watson in exchange for healing his Aunt May. His most famous duplicity was putting himself into Thanos' service until he saw an opportunity to steal the Infinity Gauntlet for himself.

1 The One Below All

Immortal Hulk vs the One Below All

The One Below All is as old as the Multiverse, sealed away in the lowest portion of Hell. A door to its realm was opened by the gamma bomb that turned Bruce Banner into the Hulk. When Bruce killed his father, the One Below All used that soul as a vessel and began to wreak havoc on Earth influencing Gamma-mutated people.  When Hulk drained Sasquatch's Gamma energy, he became the host for the One Below All.

In the far future, the One Below All used the Hulk's power to eliminate all life in the universe, including those believed to be immortal. A warning sent back in time to the Leader led the Hulk's most dangerous villain to become a host for the One Below All. His threat continues to threaten everything, everywhere.

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