Breathe in. Breathe out.

Another spike of pain racked Shirou's frame as he rested against the tree. His body was in shambles, nearly spasming in pain from the stress he was forcing his prana circuits through. Shirou bit back a gasp of pain as another tremor shocked his nearly crippled prana circuits. Of the 27 original prana circuits he had, only 5 were left barely running. His stock of 570 structurally altered nerves-turned-prana-circuits was reduced to a meagre 50.

Shirou grimaced to himself. It had taken him 10 years of blood, sweat, and tears to alter and reinforce his nerves into fake prana circuits that did not break. The only reason all 570 prana circuits survived was due to his negotiations with the Einzbern family head Jubstacheit. In exchange for his services and noble phantasms, Shirou had requested to work together with the Einzbern family for research.

The agreement worked beyond what was expected. The Einzbern family's alchemy and structural manipulation had improved by leaps and bounds with the access to several noble phantasms Shirou carried. His structural analysis proved to be equally vital as it allowed the Einzberns to perfect many of their projects.

In return, Shirou was granted more access and even assistance from the Einzberns. Together, they were able to develop his structural analysis beyond theory. Shirou's lessons in the foundation of magecraft and structural analysis allowed him to develop a style to analyse and break down most types of magecraft he was familiar with.

But one of their greatest achievements was the fake prana circuits Shirou had. The Einzberns and Shirou had found a way to artificially manufacture prana circuits. Shirou's former prana output of 30 units had been boosted to 600 in the past 10 years.

This breakthrough was the only factor that allowed Shirou to survive this long against the magnitude and calibre of his current opponent.

Primate Murder. The first seat of the Dead Apostle Ancestors.

It started a few hours earlier, when one of the Einzbern family research facilities had declared an emergency and requested immediate backup from nearby facilities. Shirou was was visiting the Einzbern manor in Germany to discuss with Jubstacheit about modernising the Einzbern computers which his father, Kiritsugu Emiya, had introduced decades ago.

When the alarm came, he was the first to respond. Jubstacheit had long since learned of Shirou's tendency to help people despite the situation. In fact, the treatment of Einzbern homunculus changed for the better after Shirou learned of them. He quickly became their favourite visitor.

When Shirou arrived at the facility, it had been utterly demolished. As if a natural disaster had hit the area, including the surrounding forest. Splotches of blood and few mangled remains were all that was left of the Einzberns. Whispering a few short parting messages for the dead, Shirou then started tracing the panicked tracks that led into the forests in hopes of finding the cause of the events.

That was when Shirou found himself ambushed by the Monster of Gaia.

The next few hours were a whirlwind of clashes between noble phantasms and an unstoppable force of nature. The forest was flattened and the surrounding area cratered from the powerful exchange between a living human armoury and a monstrous beast of nature.

Shirou glanced at both sides behind him, reinforcing his ears to hear even a sliver of sound from the movement of Gaia's perfect predator. He knew he couldn't escape Primate Murder's perfect senses. He could not run, nor could he fight at the current state he was reduced to.

What little hope he had of survival was gone after their first exchange. The White Beast of the Dead Apostle Ancestors would kill him before the Einzberns reached him. Even the combined Einzbern and Emiya resources wouldn't be enough to stop such a beast.

All he could do was delay the inevitable and buy enough time for the Einzberns to learn what they were dealing with from the messages he left behind. In the last few hours, Shirou had left many messages about the identity and the abilities of Primate Murder after each fight. The Beast of Gaia had utterly dominated the battlefield and dictated when and where the two fought. Constantly engaging and disengaging Shirou at random intervals to keep him from resting.

It was a blessing and a testament to the strength Shirou achieved after the Holy Grail War ended.

A slight breeze ruffled the leaves in the forest.

In that same moment, Shirou's instincts screamed at him of impending doom.

Shirou did not rest a moment longer and reinforced his body to dodge as fast as possible. In that tiniest fraction of a second, the tree behind him was eviscerated by claws larger than his body.

Shirou stepped on a rock and pivoted on his foot to see the face of death opening to roar at him. He jumped up, barely dodging the roar that split forest apart below him. Trees were ripped from the ground and rocks shattered underneath the intensity and strength of a wild catastrophe rampaging in the form of a wolf.

Shirou materialised a heavy sword to jump on, changing his landing direction. In a split second, Primate Murder was right below him waiting for his arrival. Shirou quickly twisted his body, narrowly avoiding the apex predator's bite that appeared out of nowhere. He flipped and kicked against the cheek of the giant monstrosity and dived straight for the ground.

After landing, Shirou immediately summoned a sword enchanted to lighten its user's mass and ducked under the massive tail swipe that would've broken his body at contact. A quick side roll to dodge the second tail swipe and he was free to increase the space between him and inevitable death.

Not even a blink of an eye, and Primate Murder charges at Shirou with the tenacity of an earthquake. Under normal circumstances, Shirou's reinforced eyes would at least see the movement, but in Primate Murder's enraged state from the wounds he inflicted upon it throughout the night, the movement turned into a blur.

Shirou knew he had didn't have the speed to sidestep the charge while also avoiding the aftershocks from each step Primate Murder made. Shirou gritted his teeth at the idea of wasting a large amount of prana to survive longer, but had no choice if he wanted to avoid dying on the spot.

His mantra appeared in his head and he dissipated the small sword for Herakles' gargantuan stone in the image of a sword. The power of Herakles' filled Shirou's body and he swung the sword forward with the strength equal to those of gods at the rampaging force of nature.

Primate Murder recognizing the powerful weapon that had wounded it several times before, slowed it's charge and shifted into a massive claw swipe to parry the great Greek superweapon. A shockwave erupted from the contact and both man and beast were flung away from each other.

Shirou smashed across the ground and coughed blood at the pain from tanking the equivalent of a hurricane. He forced his body to rise and face the beast of Gaia. His eyes widened at the large mass dropping on top of him, his body screamed at him to swing his sword at it. The great stone sword smashed into the underbelly of the massive beast and blasted it across the clearing. It smashed into the trees and toppled a couple dozen in it's path before stopping.

A moment of respite. Shirou breathed heavily after the flurry of attacks that he defended from within a span of a few seconds. His prana circuits burning, begging for him to rest.

But he couldn't.

Every second wasted was a life saved from Primate Murder's hunting spree.

And it was over. The Beast of Gaia rose from the trees across the clearing. It turned its hateful eyes at Shirou, ready for another round of attacks. A quick claw swipe at him threw a massive shockwave at his location. Shirou retaliated with his own swing and both shockwaves clashed in the middle of the field, kicking up dust and leaves around.

Shirou's eyes widened at the realisation of his mistake. Primate Murder had intended for him to react accordingly, and now, he had lost sight of the great apex predator. He quickly smashed the stone sword downwards and produced a shockwave that blew the natural smokescreen away from him.

The sound of something large flying through the air amidst the chaos was the first clue Shirou picked up. Turning around and hopping to the side before a sturdy tree crashed where he stood a fraction of a second earlier. The tree exploded into fragments at contact and scattered debris everywhere which were ignored by Shirou as he found himself staring into the gaping maw of Primate Murder.

He had been caught off guard. Shirou slammed his hands and feet against both upper and lower jaws to avoid being crushed to death. Primate Murder struggled to crush Shirou and started running him into trees and rocks.

Shirou was losing. His body spasmed and his eyes saw white as he felt the pain of breaking circuits. A few more circuits were flickering and his control over his prana was slipping. His arms lost some reinforcement and slowly weakened as each circuit broke down. Shirou went through dozens of weapons in quick succession before materialising a small knife. He chucked the knife down the exposed throat and waited.

And was promptly thrown aside like a doll. Shirou tumbled on the ground for a few metres before staring in disbelief at Altrouge's Demonic Dog choking and attempting to vomit the extremely corrosive knife.

For the first time during the entire fight, he had a chance to strike Primate Murder.

Shirou ran through some of the strongest noble phantasms he had and promptly discarded them all. He could not summon any of them in time to capitalise on the short timeframe he needed them. Most of his noble phantasms already lacked the strength or mystery to even scratch Primate Murder, a beast intertwined to the will of the planet.

To land a critical strike against one of the Dead Apostle Ancestors required you to have a mystery equal or greater than the mystery they had. The Beast of Gaia had attained the name "Primate Murder" because it simply murdered primates. Its ability is the "absolute right of killing over man" which gave it domination over primates.

There was only one object in Shirou's repertoire that could threaten such a being.

The Curse of Angra Mainyu, or rather, All The World's Evil.

In the years after the Holy Grail War's end, Shirou and Rin took care of Sakura and her curse. In an effort to lighten her pain, Shirou managed to get the assistance of the Clock Tower's Department of Curses in exchange for allowing them to have access to his share of the Angra Mainyu curse. The transfer ritual was half successful due to the nature of the curse, and the fact that Shirou's destruction of the Fuyuki Holy Grail embedded some of its fragments inside his body after the war. Using Shirou's grail fragments to reform a lesser grail allowed him to host half of the curse within Sakura.

Shirou was able to resist the curse because of his strong connection to the concept of "humanity" likely due to his self image as a "sword", a creation of "humanity". But Sakura didn't have any resistance to the curse and slowly died. Shirou and Rin made sure to spend as much time with Sakura during her last few years before she passed away.

Once Sakura was no longer around to house the curse, it naturally gravitated towards the closest host it had. Shirou struggled to control the curse and used his reality marble to contain the curse to avoid it from escaping.

It had never escaped ever since then. Shirou periodically performs checks on the curse to see if it had corrupted his soul, but it seemed that his soul of "sword" was of the same wavelength as the curse. Both being a creation of "humanity" negated the curse's pursuit to corrupt him.

But locking the curse away was different from using it.

Shirou steeled himself and materialised a knife to project the curse into. He had one chance and he needed to hit Primate Murder with All The World's Evil before the window closed. He opened his soul and willed the curse to envelop the knife.

And his mind blanked from the pain. Shirou lost control of the curse and it retreated back into his reality marble. He quickly reawakened and found himself lying on the ground with his body shaking from pain. It was too much, he couldn't control the curse. Shirou desperately racked his mind for ideas.

If he couldn't control the curse, then all he needed was to throw it at the beast before he lost consciousness. Shirou had lost Herakles' great stone sword after he lost consciousness from the pain of Angra Mainyu. He was down to his last few dozen fake circuits and estimated that he could survive one more exchange at most.

Shirou reinforced his body for one last time and dashed then jumped into the air above Primate Murder. At this point, his body was producing such a small amount of prana that the beast ignored his seemingly last ditch effort to survive. Shirou focused on pulling the curse out one last time and was rewarded with Primate Murder's horrified eyes staring at him for one moment before the cursed knife stabbed into the eye of the Beast of Gaia. The apex predator had underestimated the ability of a prey trapped against the corner and paid dearly for it. Shirou was already unconscious before seeing the effects of the curse on the great hunter of the planet.

The night passes silently as the great battle between the Grail Killer Emiya and the Beast of Gaia ends with one dead and the other retreating with injury.

Morning comes and the Einzberns arrive at a scene of battle. Far away in the Einzbern Manor, Jubstacheit receives news from the first arrivals that the facility is gone and that Shirou has been killed by Primate Murder. His body was found crushed beside a large pool of phantasmal blood with a trail dripping away into the forest.

In the next few days, the Moonlit World explodes from the news that Grail Killer Shirou landed a crippling injury on the Beast of Gaia before dying. Dead Apostle Ancestor Merem Solomon confirms this to the church.


Author's Note

This is my first time writing so I would love to have comments and suggestions on how to improve! Hopefully I don't die and lose interest in writing this fanfic. I'm really looking forward to seeing how bad I can do (lol).

This chapter is supposed to show the strength of Shirou relative to some of the most powerful nasuverse characters. He could grow stronger, but killing him here is where the fun starts. :)))

Anyways, hope you enjoyed the chapter!