The emerald swirl of the dimensional portal crackled against the clear blue Tokyo sky, drawing the attention of civilians who pointed upward at the strange phenomenon. The portal burst open, revealing a massive green figure floating above the city's gleaming skyscrapers.

Shrek, wearing his signature white peasant's shirt and brown vest that strained against his ogre bulk, surveyed the modern cityscape below with confusion. His large ears twitched at the sound of panicked screams rising from the streets. The ogre's green skin glistened in the sunlight as he turned toward the source of the commotion.

Massive red landing castles belonging to the Orbital Knights of Mars descended from the heavens, their crimson hulls casting ominous shadows over Tokyo's buildings. Leading the Martian invasion force was Count Cruhteo's castle, its angular architecture a stark contrast to the sleek modern buildings below.

"What in the name of Far Far Away is this?" Shrek muttered, watching as the first Martian Kataphrakt mechs deployed from the landing castles. The mechanical warriors, painted in deep crimson and gold, activated their purple Aldnoah drives and began raining destruction on the city below.

A familiar white-haired figure in an ornate red uniform stood at the command center of the lead castle - Count Cruhteo himself, his pale features twisted in a sneer as he directed the attack. "Show these Terrans the might of Mars! Leave no survivors!"

"Oh, I don't think so," Shrek growled, his massive hands beginning to glow with verdant energy. "This is MY swamp now!"

The first beam of green light erupted from Shrek's palm, cutting through three Martian Kataphrakts in rapid succession. The mechs exploded in spectacular fashion, their pilots barely having time to register what had happened. Count Cruhteo's eyes widened in shock as he watched the mysterious green figure decimate his forces.

"What manner of Earth weapon is this?" he demanded, slamming his fist on his command console. "All units, focus fire on that creature!"

A squadron of Martian fighters broke formation to engage Shrek, their energy weapons leaving crimson trails across the sky. The ogre barrel-rolled through their attacks with surprising agility for his size, retaliating with precise green energy beams that reduced the fighters to falling debris.

"Count Saazbaum!" Cruhteo called over the command channel, his voice tight with tension. "We have an unexpected situation-"

Before he could finish, a massive green blast tore through his castle's shield systems. The ogre had noticed the command center and decided to take out the leadership. Cruhteo's eyes widened in horror as the green energy enveloped his position.

"This is what happens when you try to take over somebody else's swamp!" Shrek shouted as he systematically destroyed the Martian forces. His green beams cut through landing castle after landing castle, the massive structures falling from the sky before they could deploy their full complement of forces.

Count Saazbaum, watching from his own castle in orbit, grit his teeth as he witnessed the destruction of his fellow knights. The nobleman's purple uniform was immaculate as always, but beads of sweat formed on his forehead as he realized the invasion was falling apart.

"Full retreat!" he commanded, his voice carrying across all Martian frequencies. "All forces, withdraw immediately! We cannot stand against this... this thing!"

But Shrek wasn't finished. The ogre flew straight up into the atmosphere, green energy coating his body as he pursued the fleeing Martian forces. His attacks were precise and devastating, leaving no landing castle intact. The sky filled with falling debris as the invasion force was systematically dismantled.

Princess Asseylum Vers Allusia, watching from her hidden location in the city below, stared in awe at the strange green savior who had single-handedly prevented the invasion she had failed to stop. Her long blonde hair whipped around her face in the wind generated by the battle above.

"Impossible," she whispered, her green eyes wide with wonder. "He defeated the combined might of the Orbital Knights in mere minutes..."

As the last pieces of Martian technology fell from the sky, Shrek hovered above the city, surveying his work. The sun was setting now, casting an orange glow across the metropolitan landscape. Emergency vehicles were already responding to the minimal damage caused by the brief battle, their sirens creating a distant chorus below.

"Well," Shrek said to himself, dusting off his hands with satisfaction, "that takes care of that. Now, where can an ogre get some onions around here?"

Another dimensional portal opened behind him, its green energy matching the residual glow from his attacks. Shrek took one last look at the city he had saved, nodded in satisfaction, and flew into the portal. It closed behind him with a thunderous crack, leaving the citizens of Tokyo to wonder about the strange green hero who had appeared just in time to save them from certain doom.

In the days that followed, conspiracy theories would abound about the "Green Guardian" who had thwarted the Martian invasion. Some said he was a secret military weapon, others claimed he was an alien himself. But they all agreed on one thing - thanks to him, the war had ended before it could truly begin.

And somewhere in a swamp in another dimension, an ogre added another tale to his collection of adventures, though few would believe him when he spoke of the time he single-handedly defeated an army of space knights with his onion-powered energy beams.

High above Earth's atmosphere, aboard the Martian satellite base Marineros Station, Count Marylcian stood at the observation deck, his tall, lean frame rigid with disbelief. His pristine white uniform and carefully styled purple hair reflected the emergency lights that had begun flashing throughout the station.

"Impossible," he whispered, pressing his gloved hands against the reinforced glass. Below, Tokyo sprawled like a glittering tapestry, but his attention was fixed on the green figure decimating the invasion force. Through the high-powered observation systems, he could clearly see Shrek unleashing beam after beam of verdant energy.

"Count Marylcian!" A young Martian officer burst onto the deck, his red uniform disheveled. "The landing castles - they're being destroyed faster than we can track!"

"I can see that, you fool!" Marylcian snapped, his aristocratic features contorted in rage and fear. "What manner of monster is this? Our Aldnoah drives should make us invincible against mere Terran weapons!"

Across the command center, other Orbital Knights watched in horror through their own screens. Count Barouhcruz, his dark skin contrasting sharply with his white uniform, gripped his command console so hard the metal groaned.

"Our shield technology... it's as if it doesn't exist to this creature," he muttered, watching another landing castle split in two under Shrek's assault. "The dimensional barriers, the absolute defense systems - all meaningless!"

A brilliant green flash lit up the observation deck as Shrek turned his attention skyward. The beam lanced through space, striking one of the orbital platforms. The station's occupants barely had time to scream before it exploded in a spectacular display of light and debris.

"He's targeting our orbital facilities!" someone shouted. "Emergency protocols-"

Another beam cut through space, this one cleaving through two satellites simultaneously. The green energy seemed to ripple and pulse, almost alive in its devastating precision.

Marylcian stumbled back from the window as Shrek's massive form appeared directly in front of the station, floating in space as if the vacuum meant nothing to him. The ogre's eyes locked with the Count's, and for a moment, time seemed to freeze.

"Better out than in, I always say," Shrek's voice somehow carried through the void, a grin spreading across his face as he charged up another blast.

"No, wait-" Marylcian raised his hands in a futile gesture of surrender, but it was too late. The green energy engulfed the station, and the last thing the Count saw was that terrible, toothy smile.

The remaining Orbital Knights in other stations watched in mute horror as Marineros Station disappeared in a flash of green light, leaving nothing but floating debris in its wake. Their sophisticated communications systems crackled with panicked chatter and desperate pleas for retreat.