Summary: Chiron always said there'd be legends about him one day. He hadn't thought that'd result in him fighting to the death with other Heroes, though. PJatO/F/SN

Disclaimer: This is a work of fanfiction using characters and materials from the works Fate/Zero and Percy Jackson. I do not own Fate/Zero, Type-Moon, or Percy Jackson. The story I tell here about those characters is my own invention, and it should not be purported or believed to be part of either story's canon. This story is for entertainment only and is not part of any official story line; any similarities between those story lines and this one should be assumed to be drawn from those story lines, should any confusion exist.

Holding Back the Sea

Prologue

XxXXxX

"Have you accurately memorized the incantations of summoning? Good…only, midway through the incantation, add two more lines of incantation."

"What do you mean?"

"Isn't it obvious…? Kariya, you should know that as a magus, your abilities are more than just a notch or two below the other Masters. It will affect the basic abilities of the Servant. If that's the case, it can only be amended through the Servant's Class, and we must raise the parameter from the root up."

Predetermining the Servant's class through alterations of the summoning incantation.

"Usually, the class is inevitably decided by the summoned Heroic Spirit's own attributes, but there were two exceptions—classes that could be designated beforehand."

One of them was Assassin, a group of killers that inherited the name of Hassan I Sabah.

And the second was a class for all Heroic Spirits and could be manifested as long as the incantation was changed appropriately.

"Give the summoned Servant the attribute of 'Mad Enhancement,' Kariya! As the Master of Berserker, fight for me was all of your strength!"

XxXXxX

"Ye first, O silver, O iron

O stone of the foundation, O Archduke of the Contract.

Hear me in the name of our great teacher, the Archmagus Schweinorg.

Let the descending winds be as a wall.

Let the gates in all directions be shut, rising above the crown, and let the three forked roads to the Kingdom revolve.

Shut. Shut. Shut. Shut. Shut.

Five perfections for each repetition.

And now, let the filled sigils be annihilated in my steed!

Set!

Let they body rest under my domain, let my fate rest in thy blade.

If thou submitteth to the call of the Holy Grail, and if thou wilt obey this mind, this reason, then thou shalt respond.

I make my oath here.

I am that person who is to become the virtue of all Heaven.

I am the person who is covered with the evil of all Hades.

Yet, thou serves with thine eyes clouded in chaos.

Thou, bound in the cage of madness.

I am he who commands those chains—"

Kariya was different from other Magi. His Magic Circuits were made from other organisms that lived in him as parasites. The pain caused by inciting them and activating his circuits was incomparable to that suffered by other magi. Even as he chanted, his limbs spasmed in agony and blood seeped from shattered capillaries. Tears began to flow from his wholesome right eye.

—But even so, his concentration did not lapse.

Thinking of the duty he bore upon his back; he would not let himself shrink back, no matter what.

"—Thou seven heavens, clad in a trinity of words,

Come past they restraining rings, and be thou the hands that protect the balance!"

Finishing the incantation, he poured all his strength into the summon. It hurt, but even so, he wished and prayed: 'Please, for Sakura's sake, let a mighty hero answer my call.'

Thunder and lightning roared. Plume of smoke filled the room, carried like storm clouds on a mighty wind. The summoning circle shone with a brilliant light, from which a bronze silhouette emerged.

He wasn't tall—an inch or two above Kariya, at most. But he was striking. He looked the part of a hero reborn, his black hair windswept, and his eyes deep green. He wore armor of polished bronze and hints of gold. On his arm was a brand like tattoo, 'SPQR,' with a trident and lines beneath.

His eyes swept the room quickly, sliding over Zouken before focusing on Kariya.

"I ask of thee—are you my Master?" Berserker asked.

XxXXxX

Berserker didn't even have time to think about question why he was here before the Grail providing him with all he needed to know.

He was a Servant summoned to fight in the Holy Grail War. His class was Berserker—a Servant that traded his sanity in exchange for power. Berserker objected to this on principle—his mind was as sharp a weapon as any blade and he could serve as a warrior better with his wits about him then he could as a mindless thug.

But it was not his place to object—or rather, his objections would not matter.

This War was fought with the purpose of obtaining the Holy Grail and granting a single wish. Because only one wish could be granted, the war was fought to decide who it would belong too. He wondered what he would wish for, but the question mattered little, if his sanity was to be taken from him. Further, his Master had three 'Commands Seals' with which to force his compliance.

So he was just a pawn? The notion raked at him—he never liked being bound or contained.

The old man that was with his master began to clap. Berserker focused on him immediately. He didn't wish to judge, but he found the main very ugly. Granted, he had…he'd had a number of friends that ranged from ugly to monstrous, so he couldn't hold it against him.

"Good…very good, Kariya. You are officially a master in this War. With your Servant, bring me victory."

His Master—Kariya—barely veiled his animosity for the man, which attracted Berserker's interest.

Once more he noticed his Master's condition—his hair was white and if he hadn't been moving, Berserker would have thought his dead. His left side was injured—or perhaps recovering from injury—and Berserker could tell it was weakened by how he favored his right side. His left eye seemed dead and he thought he could see things moving beneath his master's skin.

"Take your Servant and prepare—the Holy War shall begin soon."

Kariya grit his teeth, but he could tell it was only partially in annoyance. His Master forced himself to stand upright and began to walk out of the room. As he'd suspected, his left leg moved slowly.

Wordlessly, he fell in line behind his Master.

XxXXxX

Barely a moment after closing the door behind him, Berserker had to catch his Master as he fell.

He waited silently, as his Master gasped for air so greedily, it was like he'd been drowning.

Berserker looked at him silently for a moment before speaking.

"You are dying, Kariya." He risked using his Master's name to gauge his reaction. There wasn't one—he just nodded slightly in acknowledgement. Berserker pondered that briefly, deciding that he was either not the type to lord power, or perhaps completely unused to it.

"Where should we go now?" He asked.

Kariya made to reply, but began to choke in the process.

"Away from here." His Master gasped out.

Berserker nodded in acceptance, partially because those were his orders, and partially because he wanted to see this new city at least once before he lost his mind.

He scooped up he sickly Master and left the house in a blur of motion.

Knowing better then to draw attention, he moved quickly from the streets to the rooftops in a series of short jumps, careful not to move fast enough to further wound his Master.

He was in the process of deciding where to go—to a hotel or to attempt to find an abandoned house—when Kariya spoke up.

"Take a left down this street and take the fifth right, the second left, and the third right. That's my house."

If you have your own home, why were you in that old man's house, Berserker thought, but did not ask. Instead, he simply obeyed, arriving at the house in less than ten minutes.

Placing Kariya down outside the door, he turned himself into a spirit even as his Master began fumbling for keys. Passing through the door, he solidified on the other side and unlocked it from inside, holding it open silently.

Even as his Master slowly entered the house, Berserker surveyed the house, taking note of any details he found interesting.

It was dusty. Really dusty. It looked as though it hadn't been used in a year; for all he knew, it hadn't been. Which told him his Master didn't have a maid, further supported by the size of his house. It also raised the question of why he hadn't used the house in so long.

He frowned.

"How long have you lived here?" He asked immediately.

Kariya had shuffled over to one of the chairs and sat down stiffly.

"Several years now, ever since I left my 'Uncle's' home." Kariya said. He pronounced the word Uncle like a swear word and with a strange tone, as if his uncle was not actually his uncle. Berserker quickly associated the term with the old man and assumed Kariya wasn't fond of the man.

He wondered why; and more, why was he working with someone he hated.

But for the moment, he had bigger concerns.

"Is this house registered in your name?" He asked.

Kariya nodded.

"We'll need to find another place soon. The other Master's we learn of you eventually, if they haven't already. But we can stay here for tonight at least, and find another place tomorrow."

Kariya looked at him with his one good eye, and something fierce burnt in it.

"It doesn't matter what happens to me, as long as I survive long enough to win this war. Are you strong enough to do that, Berserker?"

Berserker looked at his quietly, and had to ask.

"What is the wish you seek, Kariya?"

Kariya made a rasping sound that Berserker couldn't distinguish as an inhale or exhale.

"Why do you wish to know?" He asked sharply.

Berserker considered dropping the subject or being more subtle.

But if he was going to have to fight in someone else's war, he at least wanted to know why.

"I am a Berserker," He said. "And once you activate the Mad Enhancement, I will probably lose all of myself. Then, I will fight to the death with respectable heroes from across all of history, to which I will seem nothing but a savage bloodthirsty beast to be killed. I do this because I am your Servant and I have to grant your wish—I think I am at least entitled to know what it is I will sacrifice my mind, body, and pride to fulfill."

His Master fell silent, apparently only now realizing what it meant to be a Servant and a Berserker.

"It's for a girl—not like that!" He replied when his Servant sighed and smiled wryly. "There's a girl who needs help."

The smile fell away from the Berserker's face.

"Do you love her?" He asked, something glimmering in his eyes. Kariya suddenly remembered that his Servant had once been a hero, with friends and loves of his own. He also realized that they were probably all dead by now, and Berserker probably knew it.

Even so, he nodded at his Servant's question.

"I do, though probably not in the way you're thinking."

"Your daughter?"

"More like a niece, really."

Berserker moved over to Kariya's chair and sat on the armrest.

"What happened?"

Anger burnt in Kariya's eye.

"Her father had two daughters and only chose one to carry on his family traditions. Zouken," Kariya spat, and Berserker quickly associated it with his Uncle. "Offered to take her in, because his heir was incapable of using magecraft."

Berserker began putting pieces together in his head.

"But you can use magecraft, Kariya. Or else I wouldn't be here."

"I walked out of that house and the world of magi the moment I could."

Berserker closed his eyes and nodded.

That was the reason his family didn't have a worthy heir. Berserker could understand, then, why he would consider himself to blame for what had happened to the girl.

But that didn't explain why he was taking part in the war. It was true that being given away by one's parents was bad, but it seemed a bit strange to go this far for it. He should know that it was not uncommon to die in a Holy Grail War.

"Why are you going so far for her, Kariya?"

Kariya lifted a shaking hand to his disfigured face.

"You wouldn't know it if you saw her, but…for all that he has done to me, Zouken has done worse to Sakura."

The Servant frowned, pieces suddenly snapping into place.

"He's done this to you? Why?"

"Alone, I could not take part in the Grail War, so for one year, I was trained. But my power is nothing compared to Sakura's. I took part in this war, because if I won, there would be no need to make Sakura suffer, and she could go back to her mother and sister. But Zouken has no faith in me, so for the year I trained, he continued to make Sakura suffer. Even if he loses this war, there will be another after it—one where Sakura's child would have to fight. If I…if we fail here, then Sakura will suffer for the rest of her life and so will her children. So I have to win." Kariya's eye rolled to look up at his Servant. "I am sorry for what I will do to you…and I am sorry for what I will have to make you do. But I cannot lose. If it makes you feel better, I won't survive long after this war."

Berserker shook his head.

"Ah. It doesn't matter. As a hero, I will of course give my life to save an innocent girl. Rest, Master Kariya."

Berserker was about to stand, but Kariya stopped him, grabbing his arm. His grip was shaking and weak and the Servant could easily have broken it. But he stopped obediently, looking at his Master.

"Please…tell me you are strong. Tell me you can really save that girl."

Berserker slowly lifted his hand to Kariya's and removed it from his arm.

"Rest now, Kariya. When you awaken, I will give you all the proof you need that you summoned exactly what you needed."

XxXXxX

It was not long before his Master drifted off to sleep. As soon as he had, Berserker reverted to his spiritual form and drifted out of the house like a ghost.

He retraced the steps he had taken to get to the house, quickly returning to the place where he'd been summoned.

For a moment, the reborn hero stood like a ghost outside the Matou Household.

And then he drifted in through the walls.

At the very least, before he lost his mind, he would do this of his own free will. He would show that he didn't need to be forced to do what was right.

That was his pride as a Hero.