Peter never intended to jump straight to Earth-616.
He had pieced Belasco's plan together back in Limbo. The demon lord couldn't breach the reality barrier of Earth-616 on his own. He needed a living anchor. He had banked on Illyana embracing her dark magic, or Peter serving as a multiversal taxi service, to smuggle him across the threshold.
Since Peter had absolutely no intention of acting as a demonic Uber, he simply changed the coordinates. He tore the spatial rift straight into the Wastelands.
Reed Richards had already established a portal network bridging Earth-616 and the Wastelands. Because of Reed's temporal engineering, the flow of time between the two dimensions was perfectly synchronized.
Those crucial few seconds gave the Black Panther on the other side enough time to radio Avengers Tower. Stephen Strange felt the multiversal tremor, grabbed every available heavy hitter he could find, and portaled them straight to Peter's landing zone in the Wastelands. The resulting army was massive—arguably a more complete roster than the one that had fought Knull.
"Belasco." Stephen Strange floated down next to Peter, his Cloak of Levitation snapping in the arid wind. "The exile. A failed lackey of Chthon, and a notorious stain among the Hell Lords."
Strange looked at the grotesque demon, then glanced down at his own ruined, depressed alternate-universe counterpart. He let out a long, heavy sigh. With a flick of his wrists, the golden, glowing Shields of the Seraphim flared into existence around his forearms. "You really know how to throw a party, Spider-Man."
"To be fair, he was planning to crash our world," Peter said.
"I see that," Strange muttered. "He's holding a Bloodstone Amulet. If that crosses into our world, it tears a rift straight to Chthon's realm. The Elder God descends. But there's a catch. The Bloodstones can only cast that specific summoning spell in the exact universe where the trapped souls originated. Our universe. The mission is simple: we snatch that amulet. Then we kick this ugly bastard back to his miserable dimension."
Strange's hands blurred through a series of somatic signs. He slammed a mystical seal over the rift Belasco had used, locking the backdoor to Limbo.
"Listen up!" Strange's voice amplified magically across the battlefield. "I'm not an Avenger, so I'll keep the tactical briefing short. He's trapped here. Grab the amulet. Try not to die. Now, hit him with everything you have!"
Steve Rogers stepped forward. He raised his vibranium shield high. "Avengers! Assemble!"
"To me, my X-Men!" Cyclops roared.
"For the glory of Asgard!" Thor bellowed, spinning Mjolnir above his head.
"It's Clobberin' Time!" the Thing thundered.
The combined might of the Avengers, the Fantastic Four, the Thunderbolts, the Defenders, the New Mutants, the Hellions, and the Wasteland Sunset Avanger charged as one.
Belasco realized he had been played. He threw his head back and laughed, a jagged, furious sound. With a sweep of his claws, a tidal wave of blood-red hellfire erupted toward the vanguard.
"You think stranding me in this dying timeline matters?!" Belasco roared over the roaring flames. "This Wasteland is still tethered to your universe! I can carve my way into your Earth from here! Do you have any idea how many X-Men and Avengers I've butchered across the multiverse?!"
Thwip. Thwip.
"Shut up, demon," Clint Barton muttered.
Two arrows buried themselves squarely into Belasco's forehead simultaneously. They didn't do lethal damage to the demon lord, but the sheer disrespect made Belasco shriek in rage.
Clint lowered his bow, standing alongside Black Widow, Ghost, and Silk. He glanced to his right. Standing shoulder-to-shoulder with him, lowering an identical bow, was the grizzled Old Man Hawkeye of the Wastelands.
Old Man Clint sighed. "It's nice looking at a version of yourself that hasn't completely screwed everything up yet, isn't it?"
Earth-616 Clint shook his head. "I really hope I don't get that cranky when I reach your age."
Belasco ripped the arrows from his skull. He couldn't retreat to Limbo, but he could still tear open smaller pockets to summon his horde. The scorched earth split open. An endless swarm of corrupted, demonic X-Men and Limbo natives poured out, crashing into the superhero vanguard like a wave of rotting meat.
Tony Stark and Cyclops ended up back-to-back in the chaos.
Tony unleashed a swarm of micro-munitions from his shoulder pods. He blew the heads off three demonic Wolverines in rapid succession.
"Hey, quick question!" Tony yelled over the explosions. "This guy's army is entirely made up of demonic X-Men! No Avengers, no Fantastic Four. Does he just really like mutants, or is this some weird multidimensional discrimination?"
Cyclops didn't miss a beat. He fired a continuous, sweeping ruby-quartz beam that bisected a dozen demons at the waist. "He targets mutant timelines because in those realities, he doesn't have to worry about humanity getting in the way!"
"Why not?" Tony fired his repulsors.
"Because in those timelines, the humans are already dead," Cyclops said flatly. He marched forward into the fray, leaving a pile of smoldering corpses in his wake.
Tony hovered in place for a second. "JARVIS," Tony muttered inside his helmet. "Remind me to leave a sticky note on the fridge at the Tower. The X-Men leader is an intense guy."
Belasco was enraged, but his mind remained sharp. He knew the demon horde wouldn't kill these heroes. They just needed to buy him enough time. If he could find the dimensional tether connecting this Wasteland to Earth-616, he could manually tear a rift and use the amulet to summon Chthon. Once the Elder God arrived, the war was over.
"Demon! You shall pay for the innocent blood you've spilled!"
Thor crashed through the demonic ranks, locking eyes with the fleeing Limbo Lord. The God of Thunder hurled Mjolnir. The hammer cracked Belasco right between the eyes.
Belasco barely flinched. He rubbed his forehead, sneering at the Asgardian. "You think you can best me with a simple hammer? I am a dimensional lord! My power transcends the boundaries of single universes! You are nothing but a localized deity on a pathetic rock!"
Thor extended his right hand. "Perhaps one hammer is not enough to fell you, demon."
Mjolnir reversed course, snapping securely back into Thor's grip.
"But fortunately," Thor said, raising his left hand, "there is more than one Mjolnir on this battlefield."
A massive sonic boom shattered the air. A second Mjolnir plummeted from the stratosphere, slamming directly into the back of Belasco's skull. The demon lord face-planted into the dirt as the second hammer flew into Thor's waiting left hand.
"Two hammers?!" Belasco roared. He pushed himself up, his jaw unhinged. "It matters not! You cannot—!"
CRACK.
A third Mjolnir dropped out of the sky, burying Belasco face-first into the crater.
Stephen Strange paused mid-incantation. He was busy weaving an enlargement spell over Giant-Man so Hank could wrestle a massive demon, but the sight made him freeze. He slowly turned his head to look at Peter, who was currently slicing through a pack of demons using Venom's symbiote blades.
"Spider-Man," Strange said slowly, staring at Thor. "Where did he get three Mjolnirs?"
Peter decapitated a demon and shrugged. "Well, I took a detour through the Marvel Zombies universe a while back."
"I thought that hammer broke."
"It did! But then the Watcher dumped me in a timeline where Deadpool slaughtered all the heroes. I found an empty Mjolnir just sitting there. Before I left, I asked Dr. Pym to hit both spare hammers with Pym Particles so I could carry them in my pocket."
Strange blinked. He looked back at Thor. The God of Thunder was currently juggling three Mjolnirs with his mind. He was treating the legendary, god-forged weapons like floating, skull-crushing artillery cannons.
For the first time in a very long time, the Sorcerer Supreme had absolutely nothing to say.
PS: Marvel Fun Fact! In the comics, we've actually seen multiple Mjolnirs in action during massive crossover events like Secret Wars (2015). In that storyline, an entire multiversal police force called the Thor Corps patrolled Battleworld, each wielding their own variant of the hammer!