From Spider-Man to the Avengers, Marvel's biggest heroes wouldn't exist in the way we know them today without Marvel's Ultimate Universe. Over 15 years, this alternate world showed readers what would happen if heroes like the X-Men and the Fantastic Four started their superhero careers in the 21st century. Starting with 2000's Ultimate Spider-Man #1, this reboot was an instant critical and commercial success that rivaled the main Marvel Universe at its peak. While the Ultimate line initially followed the main Marvel Universe's plot points, this universe eventually morphed into a much darker, weirder world that totally stood on its own. By the time it faded out in 2015, Marvel's Ultimate line had introduced Miles Morales, turned Mr. Fantastic into a supervillain, redefined Nick Fury forever and emphasized ideas that helped build the Marvel Cinematic Universe. While those are the big changes, almost every Ultimate Marvel character was drastically different from their Marvel Universe counterpart. Through these changes, some Ultimate heroes got happier lives, some went down a darker path and some got a lot more powerful.

Now, CBR is counting down the strongest heroes and villains from Marvel's Ultimate Universe. In this list, we'll be ranking these Ultimate Marvel characters by their overall power and how well they used it. For characters who went through drastic power shifts, we'll be looking at their overall strength. We'll also be factoring in these characters' biggest respective accomplishments and defeats. Even though some of these heroes have the names of the heroes your parents grew up with, these are distinctly modern takes on classic Marvel characters.

30 VAMPIRE HULK

Vampire Hulk

As his name suggests, Vampire Hulk is a version of the Hulk who's also a vampire. Created by Mark Millar and Carlos Pacheco in Ultimate Comics Avengers #3, this Hulk was originally a clone who was developed by Tony Stark's brother, Gregory. This Hulk clone kept Bruce Banner's intelligence, which ironically made him much less effective in battle.

After getting kicked out of the Avengers, this Hulk was bitten by a vampire and took over a vampire horde. Despite his immense super-strength and genius intellect, he wasn't smart enough to keep Captain America from teleporting him into direct sunlight.

29 WILLIAM STRYKER JR.

Ultimate William Stryker X-Men Sentinel

While William Stryker is a mutant-hating extremist in the X-Men movies and the Marvel Universe, his son, William Stryker Jr. filled that role in the Ultimate Universe. After his family perished in a mutant attack, Stryker started hunting mutants with Sentinel technology in Ultimate X-Men #98, by Aaron Coleite and Mark Brooks.

Ironically, Stryker also had the mutant power to control all forms of machinery and, oddly, remove mutant powers. He used those abilities to depower Rogue, launch a nationwide Nimrod Sentinel attack, briefly take over the Southwestern United States and transfer his consciousness into a Master Mold Sentinel.

28 WONDER MAN

Ultimate Wonder Man

In the Ultimate Universe, Wonder Man is one of several characters with powers derived from the serum that turned Bruce Banner into the Hulk. Nick Fury recruited disgraced bodybuilder Simon Williams for the covert West Coast Ultimates. After Williams debuted as Wonder Man in Sam Humphries and Scott Eaton's Ultimate Comics Ultimates #22, he and his team were manipulated into fighting the Ultimates.

While he usually looks human, Williams transformed into an unstable Hulk-like form when one of his missions ended poorly. The upper limits of his strength weren't established, but he held his own against a powerhouse Iron Man.

27 TYRONE CASH

Tyronne Cash Ultimate Marvel

Mark Millar and Leinil Yu introduced Tyrone Cash, another Hulk-related hero, in Ultimate Comics Avengers 2 #1. Dr. Leonard Williams was originally Bruce Banner's mentor and worked with him to create a super-soldier serum. After taking their serum, Williams transformed into Cash and wreaked havoc as an international crime boss before joining Nick Fury's Avengers.

Essentially, Tyrone Cash was a twisted version of the Marvel Universe's super-strong, super-smart Leonard Samson. While Cash had the Hulk's strength and invulnerability, he kept his intelligence when he transformed. Still, this reluctant Avenger was ultimately defeated by Blade the Vampire Hunter's vampiric hypnotism powers.

26 MAGICIAN

Magician Ultimate X-Men

The Magician was the first Ultimate X-Man who didn't have a counterpart in the Marvel Universe. Created by Robert Kirkman and Tom Raney in Ultimate X-Men #66, Elliot Boggs was a young mutant who had immense reality-warping powers. However, he could barely control them and inadvertently used them to get the X-Men to accept him.

With his mutant powers, the Magician was able to create people, control his surroundings, disrupt other mutants' powers, produce energy blasts and unconsciously manipulate complex chains of events. After the X-Men turned on him, he left to figure out how to control his powers alone.

25 PSYCHO-MAN

Ultimate Psycho-Man

In the Ultimate Universe, Psycho-Man was the ruler of the Silver Searcher's homeworld, Zenn-La. Created by Mike Carey and Pasqual Ferry in Ultimate Fantastic Four #44, Revka Temerlune Edifex Scyros III was his world's most powerful telepath and used Control-Boxes to mentally subdue the population of his world.

Psycho-Man tried to do the same thing on Earth, and it almost worked. After psychically taking over Earth's population, he transported them to Zenn-La to rebuild his fallen kingdom. With the Searcher's help, the Fantastic Four successfully defeated him and used his Control Boxes to give him the mind of a child.

24 PROFESSOR X

Professor Xavier with his cat Mystique from the Ultimate X-Men comics

Like his Marvel Universe counterpart, Charles Xavier had the most powerful mind on Earth. Like his Marvel Universe counterpart, Ultimate Professor X was his world's strongest telepath, and he also had considerable telekinetic abilities.

In Mark Millar and Adam Kubert's Ultimate X-Men #1, this Xavier debuted as the founder and leader of the X-Men. While he was a relatively moral figure, he wasn't above mind-reading, erasing memories or planting an Inception-like idea from time-to-time. With his telekinesis, he was strong enough to lift a Sentinel, but that didn't save him from Magneto's wrath during the Ultimatum crossover.

23 RONAN THE ACCUSER

Ultimate Ronan the Accuser

While Ronan the Accuser was a Kree fanatic in Guardians of the Galaxy, the hammer-wielding alien was the son of Thanos in the Ultimate Universe. This Ronan worked as a general who stopped rebellions in Thanos' interdimensional empire and debuted in Mike Carey and Pasqual Ferry's Ultimate Fantastic Four #35.

While Ronan can lift about 50 tons, his real power was in his hammer-like Ultimate Weapon, which could manipulate any kind of energy. Using it, Ronan defeated the Fantastic Four and their powerful alien allies. Ronan was only defeated when the Thing managed to use the Ultimate Weapon against him.

22 JUGGERNAUT

Ultimate Juggernaut

The Juggernaut isn't actually a mutant in the Marvel Universe, but the X-villain was a super-strong mutant prisoner of the Weapon X Project in the Ultimate Universe. After being forced to attack the X-Men in Mark Millar and Adam Kubert's Ultimate X-Men #8, he briefly joined Magneto's Brotherhood before striking out on his own.

During an encounter with Gambit, Juggernaut was given the mystical power of the Cyttorak Gem, which boosted his strength to unimaginable levels. Despite his incalculable strength, he perished after being struck by a poison dart during an anti-mutant attack in the Ultimatum crossover.

21 TESSERACT

Tesseract Ultimate Marvel

In theory, Tesseract the Everywhere Man could be completely unstoppable, but this Ultimate Universe original character didn't quite live up to his potential. Created by Mike Carey and Pasqual Ferry in Ultimate Fantastic Four #33, Tesseract was a member of Seed Nineteen, a group of alien warriors designed to fight Thanos.

With the ability to combine the abilities of his counterparts from every alternate dimension, Tesseract was a powerhouse with potentially unlimited abilities. Still, this underachiever was brainwashed by Thanos, stopped by the Cosmic Cube's automated defenses and defeated by Ronan when he was in a weakened state.

20 COLOSSUS

Bullets bouncing off Ultimate Colossus

While he still has his signature superhuman strength, Colossus only has the natural mutant power to turn his skin into organic steel in the Ultimate Universe. Since his metal skin was too heavy to move, Piotr Rasputin relied on Banshee, an addictive power-increasing compound that gave him enough super-strength to move around in his armored form.

Even after he quit using Banshee, Colossus still retained most of his super-strength. Ultimate Colossus was prone to getting into fights, and winning them. He survived a small radioactive blast and beat up Thor for 10 minutes during a fight with the Ultimates.

19 ABOMINATION

Ultimate Abomination

In Ultimates 2 #9, Mark Millar and Bryan Hitch introduced the Liberators, a team of international villains who tried to take over the United States. After developing his own version of the Hulk serum, scientist Chang Lam transformed into the Ultimate Universe's Abomination and joined the group.

Like his Marvel Universe counterpart, the Abomination was at least as strong as the Hulk and could've even outclassed him in raw power. However, he kept Lam's intelligence and didn't have the Hulk's savagery. Despite his strength, the Hulk took advantage of that in battle and gave the Abomination a humiliating final defeat.

18 GALLOWGLASS

Gallowglass Ultimate

Thanos' other son, Gallowglass, is one of the Ultimate Universe's original characters. Created by Mike Carey and Pasqual Ferry in Ultimate Fantastic Four #34, Gallowglass is the general of Thanos' armies and is made out of a highly combustible substance that's usually only found inside suns. To keep himself from constantly exploding, Gallowglass had to stay shielded by a personal force field at all times.

Besides his volatile explosion powers, Gallowglass was strong enough to defeat the Thing and another intergalactic powerhouse at the same time. Despite that, disrupting the alien's force field could permanently take him out of any fight.

17 THE CITY

The City Ultimates

After the Fantastic Four's Reed Richards broke bad, he dropped his Mr. Fantastic identity and became the Maker. The Maker developed the Children of Tomorrow, followers who evolved at a hyper-accelerated rate in the Dome. After debuting in Jonathan Hickman and Esad Ribic's Ultimate Comics Ultimates #2, the artificial intelligence that controlled the Dome evolved into a sentient being called the City.

The City could essentially become anything or produce any weapons that its residents needed to survive. After being instrumental in the destruction of Asgard and Washington D.C., the City betrayed the Maker and defeated a giant-sized Hulk.

16 IRON MAN

Ultimate Iron Man

When most versions of Tony Stark have trouble with their hearts, Ultimate Iron Man seemingly had an inoperable brain tumor. In a bizarre twist, this tumor was actually an Infinity Stone that was growing in his brain. Stark's body was full of bleeding edge nanotechnology, and the Infinity Stone only added to his already considerable abilities.

With his regular armor, Iron Man had tons of hi-tech weapons and enough super-strength to rival the Hulk. Between his nanites and the Stone's side effects, he also developed the abilities to interface with any form of technology and transfer his consciousness between machines.

15 MODI THORSON

Modi Thorson Ultimate Marvel

If his last name didn't give it away, Modi is the son of Thor in the Ultimate Universe. Unfortunately, Modi was more like his mother, Hela, than his dad. To save his child from Asgard's destruction, Thor gave Modi his hammer and hid him in the desolate Room Without Doors outside of reality.

Once he escaped, Modi used the Mind Stone and Mjolnir to spread chaos throughout the United States in an attempt to rebuild Asgard. With the Infinity Stone's mind-controlling powers, Modi was able to control Thor, destabilize the country and bend armies to his will before he perished.

14 THE THING

Ultimate Thing Bryan Hitch

In the Marvel Universe, the Thing is usually trapped in his rocky form, but his Ultimate Universe counterpart can change his appearance whenever he wants. Although he was initially even stronger and bigger than the original Thing, he eventually developed the ability to change into a jelly-like purple form and his human body.

In his rocky form, the Thing was initially strong enough to knock out the Hulk and had to wear a power dampener to keep himself from inadvertently destroying his surroundings when he moved. In his jelly form, he kept his super-strength and gained a few other abilities.

13 APOCALYPSE

Ultimate Apocalypse

In the Ultimate Universe, Apocalypse's backstory makes even less sense than usual, but he's still one of that world's most powerful mutants. Created by Brian K. Vaughan and Brandon Peterson in Ultimate X-Men #49, Apocalypse was apparently an ancient force who took over the body of Ultimate Mister Sinister.

While his powers were never explicitly stated, Apocalypse could seemingly absorb any mutant ability. He was powerful enough to trade punches with the Thing and psychic attacks with the Phoenix. Apocalypse successfully took on the combined might of the X-Men, the Fantastic Four and S.H.I.E.L.D. before the Phoenix finally defeated him.

12 HULK

Ultimate Hulk Bryan Hitch

In any universe, the Hulk is one of Marvel's strongest heroes, but he wasn't always at the top of the pack in the Ultimate Universe. After taking an experimental compound meant to replicate Captain America's super-soldier serum, scientist Bruce Banner transformed into a Hulk who was driven by his most base impulses.

Ultimate Hulk was strong enough to break Wolverine's adamantium skeleton and take on the Ultimates. He also had a powerful healing factor and the ability to adapt to almost any conditions. Despite all that, he suffered some major losses to foes like Thor, the Thing and the City.

11 NAMOR

Ultimate Namor

While Namor is usually the ruler of Atlantis, he led a less regal life in the Ultimate Universe. When he debuted in Mark Millar and Greg Land's Ultimate Fantastic Four #24, he was hibernating in a sarcophagus that marked him as one of the worst criminals in Atlantis' history. Once he woke up, he fought the Fantastic Four before becoming one of their infrequent allies.

According to Reed Richards, Namor was one of the most powerful beings on Earth. Thanks to his Atlantean mutant abilities, he was able to knock out the Thing without much effort and summon city-sized tsunamis.