Day 1: True Caster — Rain
After night fell in Fuyuki, clouds gathered and a heavy rain began to fall. The streets below were largely deserted. Only one figure walked through the downpour: a woman wearing a strange, concealing purple robe. She had no umbrella to protect her from the rain, only the hood pulled tightly over her head. She staggered as she walked, as though so exhausted she could barely stand.
The woman was Medea, the witch of legend, who had been summoned as Servant Caster for the Holy Grail War. But with her Master dead and her prana reserves nearly depleted, she lacked the strength of even a normal human, let alone an epic spirit. It seemed that her first day of the War would also be her last.
Medea's strength failed her, and her legs fell out from under her. She toppled to the ground and lay prone, one of her cheeks pressed against the wet concrete of the sidewalk. There was nothing more she could do. If she had encountered any humans, she could have killed them and consumed their souls to replenish her prana — but due to the hour of the night, and the intensity of the rain, and the fear caused by the recent serial-killings, the streets were empty. All that was left to her was to wait for death.
As she lay sprawled face-first on the ground amidst the rain, her thoughts drifted back to the series of events that had resulted in her ending up this way. Her initial summoning had gone well enough; she had been called by a Master who was a member of the Magus Association and thus had a fairly decent knowledge of strategy for combat between mages. He was also pretty dim and easy to manipulate, which suited Medea just fine. Once she had constructed her Temple and dispatched her familiars, she would be able to gather enough prana on her own that she would no longer need support from him at all. She didn't necessarily plan to eliminate him if she didn't have to, however. The Grail, after all, was an omnipotent wish-granting machine of limitless power. If its power was truly limitless, then it could be shared freely: no matter how much power Medea gave away to others, the quantity at her disposal would never lessen. Once she had the Grail, all who were worthy would be allowed to share in its blessings.
Then the other Caster appeared.
She entered the room a few minutes following Medea's summoning, claiming that she was also a Caster-class Servant who had been summoned by Medea's Master. Some kind of error with the summoning spell had caused her to be deposited a short distance away rather than inside the circle itself, but she had no doubt about who had summoned her.
Though she didn't seem to be hostile, her appearance did present the Master with a dilemma. He only had enough prana to support a contract with one Servant, not two. There was no way he would be able to bear the burden of keeping both of them, so there was no choice to but to choose one as his Servant and kill the other.
Given proper preparation time, a Caster could survive indefinitely without a direct connection to her Master by gaining prana from consuming souls. So, even if he could only form a contract with one of the Casters, it might still be possible to work with both of them. This Master, however, was not likely to trust a Servant who he was in a mere alliance with, without the security of the three Command Spells that could ensure absolute obedience. Furthermore, as a Servant without a contract, the Caster would be capable of forming an alliance with another Master should the opportunity arise and appear sufficiently tempting. No, her Master would not take that kind of risk. He would contract only one of the two Casters, and kill the other.
The other Caster talked casually about the three of them working together to win the Holy Grail. Playing innocent, acting like she didn't know that the forced suicide of one of them would be the inevitable conclusion — or who it would be, the conniving bitch. She was much younger and more attractive, with her wide eyes and her chestnut hair. Not too much going on in the chest department, but her perverted Master may have preferred it that way. Medea could tell from the look in his lecherous eyes that he was going to abandon her in favor of this younger, prettier Caster.
Memories of Jason flooded her mind. The man she had loved more than anyone else in the world. The man she had betrayed her father and country for. The man who had entered into the scared bond of marriage with. And the man who had abandoned her to marry Creusa, the younger and prettier princess of Corinth. Her Master was going to do the same thing. He was going to forsake the contract he had sworn with her in favor of some other girl.
It was too much. She couldn't bear to be betrayed again. Medea's hand clenched involuntarily, and felt the cold, hard handle of a weapon materialize within it. It was a dagger with a jagged crystal blade, a weapon which had been stained with the sin of filicide. It was from that act of ultimate betrayal, the murder of children by their own mother, that it derived its power as her Noble Phantasm. Rule Breaker, Destroyer of All Marks, the ultimate anti-magic weapon that could sever any bond — even that between Servant and Master.
Neither of them saw the attack coming. Before anyone had even realized what was happening, the wicked blade had pierced through the magus's throat. The weapon's twisty design made it largely unsuitable for killing; but against a target who was completely unprepared, it sufficed. With a Servant's strength behind it, the dull edge bit deeply enough to sever the carotid artery and jugular vein. Death from exsanguination would come within seconds. At the same time, the red Command Spells on the magus's hand burned brightly for a moment and then vanished, reappearing on the back of Medea's hand a moment later — stolen by Rule Breaker's magic.
The other Caster's eyes widened in surprise as blood sprayed from the magus's neck, but Medea wasn't about to give her the opportunity to take revenge for her would-be Master. Extending her hands in front of her, the witch of betrayal spoke an incantation in a divine language long lost to mankind. Sounds that the human voice should be incapable of producing flowed like music from her lips: the language of the gods, a single word of which could command high thaumaturgy that a modern magus would have to perform an entire aria to cast. Magic circles inscribed themselves in the air before her and fired beams of destroying light at the enemy Caster. The Servant had only scant seconds to raise a defense before being blasted by the torrential streams of power.
Amazingly enough, she actually managed to raise some type of shield before Medea's attacks struck home. Perhaps she shouldn't have been too surprised; if this strange second Caster was indeed also an epic spirit of legendary skill in the art of magic, then it would make sense for them to also be fluent in the divine language. What was strange, though, was how different the incantation sounded from any type of magic Medea was familiar with. Instead of the harmonious tones of the divine language, the Caster shouted short, distinct words, though not ones belonging any incantation that Medea had heard before.
Method aside, the defense was at least partially successful. Power responded to the second Caster's strange words as surely and swiftly as to the divine language, infusing the air around her and strengthening it into a spherical defensive barrier. The beams of prana she had unleashed did not penetrate the protective whirlwind, but instead propelled the bubble of roiling air backwards. It smashed through the side of the magus's house and was sent hurtling off into the night.
But it seemed that the mysterious other Servant would have the last laugh in the end, because Medea had expended far too much of her dwindling reserve of precious prana on that attack. Unlike Archers with their Independent Action skill, Servants of the Caster class could not last any significant amount of time without a Master supplying them a constant flow of prana. The only way for her to survive in this world without a Master would be to regularly consume the souls of many humans, devouring the magic energy that existed within them in the form of od. With sufficient time to prepare, Medea could have set up a great ritual system that would allow her to drain prana from humans all across the city, letting herself remain incarnate indefinitely without need for a Master... but because of the haste with which she'd acted in eliminating her Master, there had been no time to make any such preparations. She was instead stuck stumbling down a sidewalk trying to find any nearby humans to feed on; but it was dark and rainy, and there wasn't a soul to be seen. And because she'd expended so much of her limited power trying to kill the other Caster, she didn't even have the strength to summon familiars and send them in search of targets. Her strength having deserted her, Medea could do nothing but collapse on the wet sidewalk and wait for the end, as rain fell like tears from heaven above.
After a while, Medea realized that raindrops had ceased striking her. With an effort of will, she focused her dying senses. A stern-looking man was standing over her, holding an umbrella. He was looking down at her with apparent concern.
"Do you require assistance?" he asked.
Now was Medea's chance. If she killed this man and consumed his soul, she would gain enough strength to go on for a little longer. She could use that time to find more people, more souls, more energy, and stabilize her fading existence. All she had to do was stab him with Rule Breaker, kill him like her unlamented former Master, and she would have a chance.
And yet... she hesitated. This man had not shown her any ill will. Seeing her pain and weakness, he had stopped to offer her help. That was not something Jason would have done, or the magus who had summoned her; she could not simply treat him the same as such scum. And so, instead of reaching for her dagger, she spoke in a pleading voice.
"Help... me..." she whispered.
She was barely conscious as he lifted her up in his arms and began to carry her. Medea closed her eyes, resigned to her fate; if she was not going to consume his soul for sustenance, then there was nothing a non-magus human could do to sustain her. Her only comfort was that she would not spend her last moments in this world alone.
Everything changed, however, when he brought her back to his home. By the purest good luck, the man happened to be staying in a room at Ryuudou Shrine, a temple on the top of a mountain. The moment he carried her through the gate, Medea could sense the spiritual power of the place. It had been constructed directly above the center of the Greater Grail, the powerful ritual which would manifest the Holy Grail upon the conclusion of the War. The Greater Grail had itself been placed in this location because it was a point where several leylines converged. Almost instinctually, Medea reached down through the earth and began siphoning prana from them. Prana was found in the world in two forms: od and mana. If od could be said to be the power of human life-force, then mana was the life-force of the planet itself. Medea drank deeply from the leylines, gorging herself on Gaia's soul until her fading body ceased crumbling and stabilized.
Thus reinvigorated, Medea began speaking to the man who had saved her. She learned that his name was Souchirou Kuzuki. He had worked as an assassin and a school teacher, but had found both pursuits unfulfilling. Upon seeing Medea lying dying on the ground, however, something had moved in his cold heart, and he had decided to save her.
Since he was not a magus, Kuzuki could not truly become her Master in the sense that he was incapable of providing her with prana. But now that she had found such a rich convergence of leylines, that wouldn't be a problem. Using Territory Creation, the Class Skill of the Caster class, she was able to claim the mountain as her Temple, a special territory under her direct control. All the spiritual energy of the Ryuudou Shrine was now hers to command as she willed.
Of course, if she wanted to establish some decent defenses on the Temple, she'd need a bit more power than the leylines could provide her with: though their reserves were boundless in depth, the amount she was capable of siphoning from them was limited. The energy she drew from them was only enough to sustain her, not for her to perform great feats of magecraft. It was, however, enough for her to begin summoning some basic familiars.
"Arise, Children of the Hydra's Teeth!"
Medea scattered a handful of dragon teeth across the ground, using them as catalysts to summon her minions. The Dragon Tooth Warriors were mindless skeletal soldiers who would obey her will without question. While such low-quality constructs were unlikely to be even a minor hindrance to a Servant, they were quite capable of defeating an ordinary human and consuming their soul. Of course, wholesale slaughter would probably draw unwanted attention from the overseer of the war. Killing her original Master and taking a non-magus as a Master might have her on thin ice already, so it wouldn't be wise to cause too big of a commotion at first. Best to start slowly, until she could determine how strict or flexible he was — and whether he actually had enough power at his disposal to be a threat to her. If so, she could come up with a plan to eliminate him. In the meantime, there was no need to be greedy: she had an entire city of potential lambs to slaughter, thousands of souls which could be sacrificed to fuel her magecraft. Even if she left her victims enough od to keep them alive, she would be able to gather more than enough prana for the new plan that had begun brewing at the back of her mind.
The three red marks of her former Master's Command Spells, stolen by the contract-violating power of Rule Breaker, glowed on the back of her hand. Only one who had been deemed worthy by the Grail to serve as a Master was granted these marks. Or, to put it in other terms, bearing these marks was proof that one was worthy to be a Master. And she was a magus, after all. Not merely that, but an epic spirit of magecraft, a legendary witch whose mastery of the mystic arts far exceeded that of any modern magus. The only being that could possibly match her skill at magecraft would be another Servant of the Caster class — and since such an irregular spirit did appear to exist in this War, Medea would be well-served to find some extra advantage that could tip the scales in her favor.
Medea dispatched the Dragon Tooth Warriors to begin collecting the prana she would need from the sleeping city below, then began drawing a complicated magic circle on the ground beneath the front gate of the Ryuudou Shrine.