- For what they have done, they must pay the ultimate price!
Ultimatum is an event that took place in (publishing year) 2009 on Earth-1610. It involved all of the major heroes of the Ultimate Universe in a conflict against the master of magnetism Magneto. Ultimatum has its roots in two major titles in Marvel's Ultimate line, Ultimate Origins and Ultimates 3.
Ultimatum begins with scenes depicting the characters of the Ultimate Universe in routine circumstances. Everything seems well until a series of disasters befalls a few major cities: a lightning storm suddenly appears in New York City and a tidal wave hits Manhattan. Reed Richards and Sue Storm attempt to make it back into the Baxter Building while the Thing attempts to hold off a blue whale that crashes into the building. Giant Man breaks out of Tony Stark's mansion looking for Jan. In the flooded streets in New York City, Bruce Banner appears to have drowned only to turn into his Hulk persona. Kitty Pryde helps Peter get on his Spider-Man costume and encourages him to save as many as he can. Angel rescues an unconscious Dazzler whom he believes is dead. Iron Man proceeds to rescue Captain America, stating that many people have died and that he doesn't know where the rest of the Ultimates are. With New York City underwater and time running out, Sue Storm manages to push all the water back out of the city with a colossal force field which knocks her unconscious and leaves her on the brink of death. Reed later assumes that Namor was the one who caused the tidal wave. Namor aggressively denies any part in the destruction of New York City, his reasoning being that he would never knowingly put Sue in danger. After knocking him out, Reed wonders who it truly was. In Latveria, Doctor Doom leaves his castle to notice that everyone and everything is frozen. Professor X states that millions have died and telepathically tells Captain America, Reed Richards, Iron Man, the Thing, and Spider-Man that Magneto has arranged for all of this to happen. Magneto is then revealed to be in his floating citadel with Thor's hammer Mjolnir.
May Parker is arrested and brought to the 103rd precinct where she is questioned at length about her nephew's connection to Spider-Man. The detectives are convinced that Peter Parker actually is Spider-Man, but May offers them nothing, insisting that they allow her to contact a lawyer. Suddenly, all of the lights go out. May walks out of the building into the street only to bare witness to a scene of unheralded devastation. The Ultimatum Wave slams into New York City completely flooding the five Burroughs. Thousands of people are killed. Spider-Man swings about, desperately trying to save lives. He is scared and confused and doesn't understand why this is happening. He receives a telepathic message from X-Men leader Charles Xavier who explains to him that the Ultimatum Wave is the fault of Magneto. Magneto wants revenge against the entire world for the deaths of his children, Wanda and Pietro. In Battery Park, Kitty Pryde tries to rescue people on the L train, but many of them are reluctant to receive aid from a mutant. Gwen and Mary Jane are nearby, and are just as confused and scared as everybody else. At the precinct, Jessica Drew, aka Spider-Woman, swings down and finds May Parker outside police headquarters. May is trying to save the life of the detective, Mary Lambow, who arrested her, and is currently pinned down beneath a fallen telephone pole.
William Stryker's wife and son are killed by the Ultimatum Wave. At Xavier's school, Jean Grey tells the team that Dazzler and Nightcrawler are dead. She refuses to allow Rogue to become involved following her recent use of Banshee. Upon Toad stating that the X-Men don't trust her, Rogue leaves the mansion. A group of survivors, incensed at Magneto's actions, find William Stryker in Central Park and offer him the opportunity to lead an anti-mutant militia using armor plating scavenged from the remains of destroyed Sentinels. Rogue flies to Canada to find Alpha Flight member Vindicator, revealing that she knows he is actually former Weapon X watchdog John Wraith. He tells Rogue that he will help find former Weapon X agents who are working for Magneto. They find Sabretooth and Juggernaut in a pub and incapacitate them. William Stryker and his armored death squad begin hunting mutants in upstate New York; their first act of violence is against Syndicate.
Following the Ultimatum Wave attack, Franklin Storm is found dead, Sue is in a coma, and Johnny is missing. The Thing is alone at the Baxter Building while Mister Fantastic searches for him. Thing travels to Pinehead Buttes, Montana in search of Dr. Arthur Molekevic. Josie and her team lead Thing down into the caverns where Dr. Molekevic is discovered, imprisoned by the Lava Men. Thing manages to rescue him and return to the surface. Upon reaching New York, Molekevic agrees to help Susan in any way he can; after examining her, they conclude that they will have to travel into her body. Dr. Molekevic asks Thing if he has access to Pym Particles.
Hulk assists Spider-Man in freeing a New Yorker trapped beneath a car. At the Triskelion, Iron Man arrives with Captain America's lifeless body, and convinces Carol Danvers to put Cap on life support. Hawkeye volunteers to help Hank Pym search for Jan, stating that nobody deserves to suffer the loss of a loved one. Back at the Baxter Building, Ben Grimm watches over Sue Storm, who remains comatose after saving the city. Her powers remain active but uncontrolled, and Grimm nearly falls victim to her unrestrained telekinesis. Meanwhile, Doctor Doom and Zarda confront Reed Richards, for help in stopping Magneto, which necessitates retrieving Nick Fury from the parallel universe which is home to the Squadron Supreme. Thor seeks the land of the dead to save Valkyrie and is confronted by Hela, who forces Thor to battle Hela's army of fallen warriors to reach Valkyrie. Captain America appears, implying that he died in the Triskelion. Hawkeye and Hank Pym notices something on a flooded New York street: Blob eating the remains of the Wasp. Meanwhile at Xavier's Institute for Gifted Children, Magneto confronts Professor X. Magneto tells him that the deaths of Quicksilver and Scarlet Witch "merely opened [his] eyes", stating that man has been in the constant decline spreading disease, war, ecological ruin, and famine. Magneto alludes to the biblical flood, but Xavier says that Magneto is not God, and that upon captured or death, he will be recalled as a monster. Enraged, Magneto snaps Xavier's neck.
The Daily Bugle staff relocates to New Jersey where J. Jonah Jameson starts writing articles to support Spider-Man after witnessing his daring acts of heroism when the Ultimatum Wave hits. As Spider-Woman rescues Aunt May, Spider-Man persuades the Hulk to help save people from the Ultimatum Wave. After Hulk uses his power claps to douse some building that were on fire, he and Spider-Man find the body of Daredevil. When Hulk regresses to Bruce Banner, he blames himself for the carnage that has happened. Spider-Man tells him that it wasn't him who caused the damage which Bruce was witness to, but Banner is inconsolable. He asks Spider-Man to kill him, as he transforms back into the Hulk, who attacks Spider-Man. While Spider-Man swings over to Greenwich Village to escape, he sees that the Sanctum Sanctorum had been hit by the Ultimatum Wave; dozens of demons emerge when the Sanctum Sanctorum's roof collapses.
General Thunderbolt Ross shows up to oversee the Thing and Dr. Molekevic's mission. They prepare a vehicle that they will use to travel into Susan's body. When the Awesome II vehicle is complete, Dr. Molekevic and Thing head into her body and go through various parts to get to her brain stem. When they get to the brain, Molekevic uses his laser to stimulate the appropriate section. They fight off the remaining nano-bug on their way out (at rapid speeds since the bug damaged their size-holding processor). As Susan Storm wakes up, Ben is offered a job as a test pilot for the Army. Sue discovers that the nano-bugs were created by Reed for some unknown reason. She uses this discovery to postulate that they can find Johnny if he has the same bugs in his system since they give off a microscopic signal.
William Stryker's Sentinel units invade the X-Mansion and managed to deliver the final blow on Syndicate. At Department H, Rogue convinces Sabretooth to help out while John Wraith does the same for Juggernaut. Rogue receives contact from Psylocke that William Stryker's goons have invaded the X-Mansion. When William Stryker's group surround the school, Liz Allan (who had just joined the X-Men as Firestar) starts throwing fireballs at them. One of Stryker's men fires at Liz, but Toad blocks the attack and is nearly killed. Rogue and the others arrive. One of them fires a poison dart into Juggernaut's eye where he apparently dies in Rogue's arms. Rogue gets angered by this and attacks William Stryker.
Mystique taunts Magneto about destroying the world for his "little girl," and some of the mutants begin turning on Magneto for killing other mutants (seen as "turning on his own people"). After killing the Madrox clone that stated that, Magneto quotes "After the great flood, God spared only Noah and his family. He did so because he knew they'd be loyal. They were the last of mankind. Now, I will choose who lives and dies. Those that remain will be grateful, for they will find themselves in heaven on Earth." Hank Pym, furious at the death of Janet, bites Blob's head off before carrying her body back to the Triskelion. The X-Men are also mourning their dead, and Angel swears he's going to kill Magneto for what he's done, and when Jean tries to reach out to the professor, she tells the others that he's dead as well. Thor officially sacrifices his life to save Valkyrie and Captain America from Hela's realm. Meanwhile, a horde of Jamie Madrox's dupes act as suicide bombers, attacking Ultimates headquarters as Iron Man and Carol Danvers struggle to hold them off. Eventually, Hank arrives back and realizing the direness of the situation. He sacrifices himself to destroy the clones by taking them out to the water, but not before instructing Tony to take Wasp's dead body and find an encrypted file titled "The Jocasta Project". Captain America wakes up not long after. He is infuriated by the death of both Hank and Janet, the woman he loves. Captain America then orders the Ultimates to gather all the remaining heroes as they are going after Magneto.
While looking for Human Torch, Invisible Woman, Thing, Mary Storm and Doctor Molekevic go to Atlantis and battle Namora, Doctor Dorcas and a Tiger Shark. When they are defeated, Invisible Woman uses the Equinox Antenna find Mister Fantastic's signal in the Squadron Supreme dimension and Johnny's signal is in a hell dimension.
Jamie Madrox's duplicates attack the X-Mansion and Rogue uses her powers to copy his in order to fight them. Wolverine heads to the Savage Land to find Jamie Madrox. With the help of Ka-Zar, Wolverine finds Jamie and kills him.
Mary Jane gets angry that Kitty sent Spider-Man out to save people. Kitty leaves to get Spider-Man back. Spider-Man and Hulk enter the Sanctum Sanctorum and fight various demons. They then encounter Doctor Strange who has been overtaken by Nightmare. It turned out that Nightmare possessed Dr. Strange's (dead?) body and has been responsible for the demons that have been released from Dr. Strange's house. In the midst of the battle, Nightmare attacked Spider-Man and Hulk. Nightmare creating the hundreds of dead bodies Hulk killed as a part of his nightmare and re-created Peter's villains/fears in the shapes of the Green Goblin, Venom, Carnage, a dead Uncle Ben, and numerous others, leaving Peter to wonder if being a hero was really worth all the death and suffering. However, upon solidifying into a young-looking purple being, the Hulk attacks him in response to the nightmares. Nightmare tries to escape through a portal which the Hulk proceeds to smash, creating an explosion with Peter and the Hulk trapped in the center of the blast.
After being freed from Nightmare, Doctor Strange then tries to take on Dormammu who emerges after Strange's house is destroyed by the blast. However, Dormammu (who is channeling Johnny Storm's flame) kills Doctor Strange. Then Ben and Sue appear, ready to take on Dormammu. In the Supreme Power universe, Mister Fantastic, Doctor Doom, Zarda, and Arcanna approach the exiled Nick Fury telling him they need his help, and that Magneto is destroying the planet and wiping out mankind. Of course Nick knew all about Magneto's endtime plan, but tells Doctor Doom that he has to come clean with the others or he won't come back with them. Doctor Doom does so, admitting that he had the Scarlet Witch murdered so that he could then swoop in after the battle between mutants and humans and rule everything. Meanwhile, the Ultimates and Wolverine burst into the Citadel to take down Magneto. Angel swoops in through a window, but is immediately slashed open by Sabretooth and bites off one of his wings. Hawkeye blinds Sabretooth by shooting him through the eye with an arrow after he was found eating on Angel's wings. Magneto then gets his arm cut off by Valkyrie (who wants to reclaim Thor's hammer) and then attacks and slices Valkyrie's throat, but she survives. Captain America then bursts in hitting the back of Magneto's helmet with his shield, to which Magneto collapses the ceiling on them, trapping them in the rubble. He flees the scene and cauterizes his arm with his magnetic abilities. When he runs into Cyclops, Phoenix, Wolverine, Storm, Hawkeye, and Iron Man, he is prepared to strike, and immediately quotes biblical verse once more before as the heroes pause before attacking him.
It is only hours after the Ultimatum wave hit. This story continues from last issue, where the Hulk was seen causing a massive explosion. Now, Spider-Woman enters the destroyed Doctor Strange's house. Out of the rubble, the Hulk emerges, either possessed or simply in a rage, the Hulk chases down Spider-woman. If not for aiding S.H.I.E.L.D. helicopters, Spider-woman would be dead. The Hulk lost sight of Spider-Woman after been blasted at by the choppers, and he fled. Spider-Woman then starts to look for Spider-Man. After failed attempts to find him, Kitty arrived to the wreckage, and the two helped citizens get to higher grounds. After a flood from a sewer erupted, Kitty and Spider-Woman found, along with countless bodies, Spider-Man's mask. No such luck for finding Spider-Man would come, and the next morning, Kitty arrived to Aunt May's house with horrible news...Spider-man is gone. Kitty handed Mary Jane Spider-Man's mask.
Wolverine attacks Magneto with the intent to kill him. After hitting Wolverine upon setting off Cyclops' visor and Iron Man's lasers, Magneto manages to kill Wolverine by ripping the adamantium from his bones after Wolverine managed to stab Magneto in the chest. Nick Fury then arrives with Mister Fantastic, Doctor Doom, and Zarda and implements his contingency plan. Using Jean's telepathy, Fury transmits his memories to Magneto showing him that the existence of mutuants was in fact the result of a misguided genetic super soldier experiment. Disillusioned, Magneto immediately reverses the damage he had done to the magnetic poles and allows Cyclops to decapitate him with his eyebeams. The heroes then leave the Citadel without Wolverine's body, believing him unable to survive Magneto's attack. Magneto's base is then destroyed with the possibly still living Wolverine left inside. Eight days later, the world has begun to recover from the devastation. Cyclops gives a speech in Washington D.C. near a crowd of anti-mutant protesters. He acknowledges Magneto's crimes, but pleads for peace between humans and mutants. He also announces that Congress is currently voting on a bill that will require all mutants to turn themselves into the US government, or be shot on sight. However, Cyclops is suddenly shot in the head by an unknown shooter. Meanwhile in Latveria, The Thing arrives in time to crush Dr. Doom's head in his hand. In Wundagore, Quicksilver is revealed to actually be alive, and confirms that he was the one who assassinated Cyclops. He then takes Magneto's helmet and swears to carry on his father's dream, all while in the presence of Mystique, Sabretooth, and an unknown woman whose face is not shown.
The book then ends with a dedication to the writers and editors who helped found the Ultimate line of comics.
Following the Ultimatum storyline, each Ultimate title is given a "Requiem" follow-up series, dealing with the status each book's characters in the aftermath of Ultimatum.
- Angel - Killed and partially eaten by Sabretooth. (Ultimatum #4)
- Beast - Drowned in the Ultimatum Wave. (Ultimatum #1)
- Blob - Head bitten off by Hank Pym. (Ultimatum #3)
- Cannonball - Blown up by Madrox. (Ultimatum #3)
- Captain Britain - Blown up by Madrox. (Ultimate X-Men #100)
- Cyclops - Shot in the head by Quicksilver. (Ultimatum #5)
- Daredevil - Found dead by Spider-Man. Presumably drowned in the Ultimatum Wave. (Ultimate Spider-Man #131)
- Dazzler - Drowned in the Ultimatum Wave. (Ultimatum #1)
- Detonator - Tortured and killed in the Savage Land. (Ultimatum #3)
- Doctor Doom - Head crushed by the Thing. ("Ultimatum" #5)
- Doctor Strange - Killed by Dormammu after his body is constricted, causing his engorged head to explode. His body is taken by a mysterious person. (Ultimatum #4)
- Emma Frost - Blown up by Madrox. (Ultimatum #3)
- Forge - Tortured and killed in the Savage Land. (Ultimatum #3)
- Franklin Storm - Killed by the Ultimatum Wave. (Ultimate Fantastic Four #58)
- Hard-Drive - Tortured and killed in the Savage Land. (Ultimatum #3)
- Hank Pym - Blown up by Madrox. (Ultimatum #3)
- Juggernaut - Hit in the eye by a poisonous dart shot by a Sentinel soldier. (Ultimate X-Men (#99)
- Longshot - Tortured and killed in the Savage Land. (Ultimatum #3)
- Lorelei - Killed by Wolverine. (Ultimate X-Men #100)
- Madrox - Killed by Wolverine. (Ultimate X-Men #100)
- Magneto - Head blown off by Cyclops. (Ultimatum #5)
- Nightcrawler - Drowned in the Ultimatum Wave. (Ultimatum #1)
- Polaris - Blown up by Madrox. (Ultimatum #3)
- Professor X - Neck broken by Magneto. (Ultimatum #2)
- Psylocke - Listed by Marvel as dead, though her death was never shown.
- Sunspot - Blown up by Madrox (Ultimatum #3)
- Syndicate - Dead after one of his heads is blown off by William Stryker. (Ultimate X-Men #99)
- Thor - Surrendered his soul to Valhalla. (Ultimatum #3)
- Toad - Listed by Marvel as dead, though his death was never shown.
- Wasp - Partially eaten by the Blob. (Ultimatum #2)
- Wolverine - Completely shredded by Magneto. Rumours that he may return were soon quieted.
- Firestar - MIA, revealed to be alive in Ultimate X #4.
- Havok - MIA, revealed to be alive in Ultimate X #5.
- Nightmare - Presumably dead after the Hulk destroys Doctor Strange's Orb of Acmantata. (Ultimate Spider-Man #132)
- Spider-Man - MIA (Ultimate Spider-Man #132), revealed to be alive in Ultimatum: Spider-Man Requiem #2.
Ultimatum was met with an almost universally negative reaction from reviewers and fans alike. IGN listed Ultimatum as one of the worst comic book events ever created. 
- No trivia.