After three episodes of relentless fallout, Invincible Season 4 is anything but a clean reset. The world is still picking up the pieces from the Invincible War, but for Mark Grayson, the damage feels far more personal. Whether it is nearly crossing the line against the Dinosaur Man or making the impossible call to kill Rus during the Sequid outbreak, his choices are getting heavier and harder to justify. The question is not just about saving people anymore, but how far he is willing to go to do it.

Around him, nothing feels stable either. Eve is struggling with powers that no longer respond the way they should (happening because she is pregnant, which Mark at the moment, is unaware of), the Guardians are stretched thin against threats like the Flaxans. Even Oliver is stepping into dangerous territory, trying to prove himself in a world that is only getting harsher. Meanwhile, far beyond Earth, the Viltrumite Empire is quietly tightening its grip, setting the stage for a conflict that feels inevitable.

And just when everything seems to be spiraling in a familiar direction, episode 4 takes a sharp, unexpected turn, pulling the story into a place the show has never gone before and bringing back a presence no one saw coming.

(Warning: This article contains spoilers. Reader discretion is advised.)

Episode 4, HURM, opens on a shaken Mark Grayson, who confesses to Art that he nearly killed someone, aka Rus Livingston, as seen in the previous episode—and would have, if Oliver had not stepped in. Mark insists it was not Livingston's fault, as the leader of the Sequids possessed him. He describes having his hand around the guy’s throat and going through with it without a second thought. In that moment, all he wanted was to eliminate the threat to his brother, Oliver. What Mark fears is how he exhibited the same rage his father, Omni-Man, has, someone he never wants to become. Ever. 

Art tries to ground him, reminding him that he did not actually kill the person, but Mark pushes back, saying he would have if Oliver had not stopped him. Worse, Oliver was terrified of him, unable to even recognize his own brother through the rage. Art, however, refuses to let him spiral. He argues that the very fact Mark feels this guilt, that it is eating him alive, is proof enough that he is nothing like Omni-Man and never will be.

When Mark says, “I crossed the line,” Art offers a hypothetical: if he were possessed and about to hurt people, and killing him was the only way to stop it, he would be grateful all the way to the pearly gates. He reminds Mark that deep down, he is still the same kid who wanted to make the world a better place; it is just that the world has not made it easy. He tells him that if he truly believes he does not deserve the suit, he should not wear it, but when he remembers who he used to be, he will know when to put it back on.

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Just then, Mark gets a call from Eve about a situation.

In Hell, Volcanikka makes a dramatic entrance, facing Damien Darkblood. Her arrival is almost god-like, filled with grand declarations about being unburnable and wielding smoldering power. She summons multiple volcanic creatures, Magnamites, from the lava at once, immediately asserting dominance. Damien, alongside his sister Domina, attempts to stop her, but Volcanikka makes it clear she wants the Infernal Throne.

A brutal battle follows. Despite their efforts, Damien and his sister are completely outmatched. Volcanikka grabs Damien by the throat, burning him, while his sister launches a counterattack. For a brief moment, it seems like they might stand a chance, but she regenerates quickly and annihilates Damien’s entire army. The most devastating blow comes when she kills his sister in a horrifying way, injecting lava into her body.

“And then there was one,” she declares, leaving Damien as the sole survivor. With no other option, Damien gathers the remains of his fallen clan and summons Satan. When Satan appears, it is clear he is not at his full strength. He acknowledges their defeat and admits that his plans have been failing one after another. As Domina’s severed head falls, he coldly remarks on how even scraps can satisfy his hunger. Damien pushes back, urging him not to lose himself to bitterness.

Satan, somewhat composed, admits his powers have diminished but promises to restore them over time. He praises Damien’s loyalty, even after past betrayals, and suggests resurrecting the clan again, but Damien refuses, knowing they cannot survive another encounter like this. Instead, he reveals he still has blood from the Guardians’ crime scene and intends to use it for something far more crucial.

As Damien begins the ritual, Satan restores the bodies of the clan, bringing Domina back to life. Using the preserved blood, Damien summons Mark, revealing that Omni-Man’s blood runs through him. Mark arrives confused, pulled straight out of a fight on Earth involving Ka-Hor, who ends up taking a female host in the chaos.

Back in Hell, Damien introduces Mark to Satan. Mark immediately assumes Satan is the problem and tries to attack him, but Damien stops him and takes him aside. What follows is a revelation that completely shifts Mark’s understanding of Hell. Damien explains that Satan is not evil and that human perceptions of Hell are largely misconceptions.

He then breaks down the concept of different ages of existence, revealing that humanity exists in the sixth age, unaware of the previous ones. The fourth age, he explains, was complete chaos, dominated by the Viles, ancient, unkillable beings who somehow survived into the fifth age. A war that lasted for eons followed, where demons fought relentlessly to contain them. Hell, as it exists now, is not a place of punishment but a prison, created by demons to trap the Viles and keep them weak through constant torment. Without that sacrifice, Damien makes it clear, Earth and humanity would not exist at all.

Now, Volcanikka plans to undo all of that by releasing the Viles onto Earth, which would mean total annihilation. That is why they need Mark’s help.

Mark is hesitant. He questions working with demons, unsure if he is the right person, especially given his current mental state. But Damien insists there is no other option; things are already at their worst. Eventually, Mark agrees with one condition: he will not hurt anyone.

The plan is simple: retrieve Satan’s crown from the bottom of a seemingly endless pit, restoring his power. As Mark and Damien descend, the journey takes an unexpectedly humorous turn. Their back-and-forth becomes a running gag, especially around Damien’s constantly shifting helmet, Mark repeatedly questioning why he keeps removing and putting it back on, only for Damien to casually insist it helps him speak clearly and, more importantly, that it “looks cool.”

Alongside this, the two slip into surprisingly deep conversations, debating the existence of heaven, morality, and the nature of good and evil. The mix of sharp humor and philosophical questioning adds a layer of levity to what is otherwise a high-stakes, intense mission.

At the bottom, they retrieve the flame guarding the crown, fighting off Magnamites along the way. Mark manages to save Damien during the ascent, and together they return with the crown. Once restored, Satan regains his full power in a dramatic and unexpectedly humorous transformation, declaring, “I am back,” while reveling in his restored strength.

With Satan restored, the battle against Volcanikka resumes. Mark fights alongside the Darkblood clan, taking down magnamites and repeatedly striking Volcanikka. Despite being overpowered multiple times, she continues to regenerate, proving nearly impossible to defeat. Eventually, she retreats, but not before setting the stage for something worse.

The Viles begin to emerge, attacking Mark and forcing the demons to return to containment efforts. With the immediate threat handled, Damien ensures Mark can return to Earth, warning that future threats may be even greater.

Back on Earth, things remain tense. Eve reveals to William that she is pregnant, but admits she is not ready to tell Mark yet. Meanwhile, Mark quietly returns to Art’s shop and takes back his old suit, signaling a shift in his mindset.

At home, Debbie discusses moving into a new house with Paul, and Oliver supports the idea once Mark agrees. Eve finally meets Mark, intending to share her news, but she hesitates when she sees he is already overwhelmed. As they talk, Mark admits he is not okay.

Before anything more can be said, two figures appear in the sky, Omni-Man and Allen.

“I’m sorry, Mark. There is no other way. The time for war is upon us.”

In the post-credits scene, Damien stands overlooking the city when he hears a voice calling him back to duty, hinting that the coming war on Earth will require his investigation once again.

With Omni-Man and Allen returning to pull Mark into the larger conflict, the story now shifts firmly toward the Viltrumite War, a major arc where Earth and the Coalition face the empire head-on. Mark will be forced into uneasy alliances, especially with Nolan, as the war tests not just his strength, but his morality, which is already shaken up as well. The arrival of stronger Viltrumites like Thragg could push him beyond anything he has faced before Eve’s pregnancy, and Mark’s internal struggle hints that the biggest battle may not just be out there in space, but within him.

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How did you find episode 4 of Invincible season 4? What do you think will happen in episode 5? Let us know in the comments.