Fuyuki was normally fairly quiet around the night-time hours. Key word being "normally."

On this particular night however, things were about to take a turn.

In the middle of Fuyuki river, a robed individual stood on the water looking up at a ginger young man on the bridge. This robed individual was Caster. Gilles de Rais after Jeanne d'Arc met her end.

Caster: "Come down, Ryuunosuke!"

Ryuunosuke: "I haaaaaate yoooou!"

Caster: "Come on, I healed you, didn't I?"

Ryuunosuke: "Yeah, Imma just stay up here."

Caster: "Ah, how magnificent. With this grimoire, written by someone calling themselves Fingering Muffin, I'm going to summon Cthulhu!"

Caster then opened his book and began reciting from one of it's pages when a bolt of lightning struck him.

Caster: "DAMN YOU, FINGERING MUFFIN!!"

Within a few moments however, a pink mist was covering the river as a massive tenticular horror spawn rose out from the mist and Caster's shrill voice screeched to the high heavens.

Caster: "I'M COMING TO GET YOU, GOD!! FUCK YOU, CREATION!! SUCK IT!!"

As the creature rose to the sky, The masters arrived in various manners. Irisviel, Kariya, Y/n, Ophelia and Sakura all arrived via Irisviel driving them there while Waver arrived with Rider on the Gordius Wheel. Lancer showed up not long after on foot with his master presumably being a pussy and hiding from the fighting. FemGil was currently with her master on a divine construct known as Vimana, the sun chariot, high above the creature.

Irisviel: "How are we going to deal with this?"

Y/n: "Do I hear anti-fortress noble phantasm?"

Saber: "I do have that... But the civilians..."

Y/n: "Aim it away from the acceptable casualties."

Everyone looked at Y/n for a moment as if he was crazy.

Yang: "I can try and hold it off."

Iskandar: "As can I."

Saber: "I'll try and defeat it normally, if not, then I may have to use Excalibur."

Irisviel: "Saber..."

Lartoria: "It's best if you just do it. Means less screwing around."

Mordred: "Agreed. That thing's probably gonna start spewing out tentacle freaks soon as well."

Gilgamesh: "Y/n. Say the word and I'll prepare for Adi la basi, Mulki."

Y/n: "Right."

Kariya: "What's whatever he just said?"

Enkidu emerged from astral form with a grim expression.

Enkidu: "We'll only use that in an extreme emergency. Adi la basi, Mulki is an extremely powerful noble phantasm that combines, Gilgamesh, mine and Y/n's power."

Irisviel: "Then why is it a last resort?"

Gilgamesh: "Because if we were to unleash it, we could potentially level Fuyuki."

Enkidu nodded as Irisviel and Kariya went wide-eyed. Y/n turned to Lancer as he prepped to go fight the creature.

Y/n: "Lancer, you seem a bit more reckless than before. I need you to not be that way right now."

Lancer: "With all due respect, I cannot sit idly by as this creature terrorises the city! I have been denied a great many fights in this grail war and I am NOT about to sit this out."

Y/n: "... So you're going to take your frustrations out on-"

Lancer: "Ironically on that big floppy thing, yes."

Y/n: "*sigh* Saber Diarmuid."

At the mention of his name, Diarmuid dropped out of astral form behind Y/n.

Diarmuid: "Allow me to guess. You want Lancer and I to spearhead the charge in this?"

Y/n: "If it's regenerating too quickly, then pull back and Saber will unleash Excalibur."

Ophelia: "Diarmuid. Likely you'll face a lot of resistance out there, so let Zhuge buff you and Lancer before you go."

Diarmuid nodded as Zhuge stepped up and used his skills to buff all the servants present.

Iskandar: "I'll try and put some dents in it as well."

Kariya: "Berserker, think you can help out?"

Zerkerlot emerged from astral form as Kariya winced. The worms inside of him were causing him an absurd amount of pain. Y/n knew that Kariya would die at the end of the war, so he wanted to at least make it a peaceful send-off when the time came.

With that said, Iskandar took off in his chariot as Lancer and Saber Diarmuid both ran out to fight Caster.

Saber ran out across the water's surface as well while Mordred ran along with her.

Lartoria: "What're their chances?"

Y/n: "Caster's regeneration will likely be too fast for them to deal any substantial damage. We'll need Excalibur."

Zhuge: "May I also suggest something?"

Y/n: "Go for it."

Zhuge: "Bheathach Siorriudh."

Irisviel and Kariya were confused at the name until Y/n frowned.

Y/n: "Ideally I'd like to save it for the fight against avenger, but you're right. Bheathach Siorruidh might be our best option."

Irisviel: "What exactly is Bheathach Siorrudh?"

Y/n: "In a sense, it's one of my personal noble phantasms. Despite the fact that I'm human and very much still alive, my being has been fused with a primordial god which gives me access to his power. Mix that with my magic and it allows for me to summon my own noble phantasm."

Kariya: "Wait, Magic? Not magecraft!?"

Y/n: "That's right. I'm a magician, not a mage."

As Y/n spoke, one of the tentacles from Caster's noble phantasm came down to try and crush him. As it did so, Y/n smirked.

Y/n: "Which means I can do shit like this."

With a smirk, Y/n snapped his fingers and deployed magic blue to completely halt time around him as he moved out of the way of Caster's attack before he summoned Bheathach Siorruidh and severed the tentacle with a single slash. He then snapped his fingers and resumed time's flow.

From Irisviel's and Kariya's perspective, Y/n had simply blinked over to where he now stood, which was when they noticed the sword in his hands.

Irisviel: "Th- That sword!"

Y/n: "This is Bheathach Siorruidh. The sword of the eternal oath. Born of the fusion of my power and Excalibur."

Y/n turned and saw that the tentacle he had severed was regenerating at a rapid rate, the other servants were having a tough time doing any damage to the monster as well.

Y/n: "Alright. ALL SERVANTS, GET BACK TO SHORE! WE'RE GOING WITH PLAN B!"

The servants all looked over and made their way back to the riverside.

Iskandar: "This thing's tough. Too bad it's the machinations of a madman."

Y/n: "Saber. You good to use Excalibur?"

Saber: "I should be. We need to divert it's attention."

???: "Leave that to me."

Everyone turned as Jalter walked over with her eyes glazed over with anger.

Jalter: "Lemme show you guys why the avenger class got it's name!"

Jalter sprinted forwards onto the river and she jumped over the tentacles that were surrounding her rapidly. Caster then spotted her.

Caster: "J- Jeanne? My Jeanne? Could it truly be you?"

Jalter: "I swear, I'M GONNA BURN YOUR ASS, GILLES!!"

Jalter swiped her flag in front of her as flames coated the river before her. Caster shrieked as he felt the flames burn.

Jalter: "HEY! PUPPET BITCH! GET A MOVE ON AND USE YOUR NOBLE PHANTASM!!"

Y/n: "Saber, let's go!"

Saber watched as Y/n ran onto the river and she chased with him. Mordred and Lartoria followed close behind. The four stood in front of the creature as it was distracted before Saber held Excalibur aloft. Mordred did the same with Clarent and Lartoria prepared to thrust Rhongomyniad forward. As they did so, Y/n got ready to sprint in front of the blasts.

Saber: "... Sheathed in the breath of the planet lies a torrent of shining light. Feel it's wrath..."

Mordred: "This is the evil sword that killed my father. I will do all I can to bring the king peace..."

Lartoria: "Removing the thirteen restraints, O light, may you be released from the ends of the world. Split the heavens and tether the earth, anchor of the storm..."

Y/n sprinted out and drew his sword as the three unleashed their noble phantasms.

Saber: "EX... CALIBUR!!!"

Mordred: "CLARENT BLOOD ARTHUR!!"

Lartoria: "RHONGOMYNIAD!!"

Y/n smirked as he saw the blasts tearing towards him. He then stopped and stabbed Bheathach Siorruidh into all three beams as they suddenly dissipated and were absorbed into the sword.

Y/n: "My turn! EXHAUST THE CONCEPT OF ANNIHILATION! EXHUME THE CONCEPT OF DEATH! GO FORTH AND INFLICT DEVASTATION!"

Y/n leaped into the air and raised his sword into the air as he aimed down towards the creature. The energies of the three absorbed noble phantasms swirled around the blade as it was about to unleash every ounce of energy it had absorbed as well as it's own power.

Y/n: "BHEATHACH SIORRUIDH!!!"

The sword was brought down and the night shifted to day as it's power was unleashed. All of the servants present watched in awe as the sword of the eternal oath completely annihilated Caster's monster.

Ryuunosuke stumbled back as he saw Caster disintegrate.

Ryuunosuke: "N- No way..."

As he tried to back up, he bumped into someone. He turned around and found Kiritsugu with a gun aimed at his head.

Ryuunosuke: "I- I don't suppose we can talk about this?"

Kiritsugu: "No."

The trigger was pulled and Ryuunosuke fell to the ground with a bullet-hole between his eyes. Both Caster and his master were no more.

Y/n descended from the sky after unleashing Bheathach Siorruidh as his consciousness began to fade. As he fell however, he was caught by FemGil as she sat upon the throne on Vimana.

FemGil: "You have my respect, Chaldean. I wasn't expecting you to have such power, yet I find myself surprised."

Y/n tried to get to his feet, however he found himself weakened by the use of the sword.

Y/n: "This didn't happen last time I used it..."

FemGil: "Then consider this. You used your sword in conjunction with another three noble phantasms. Instead of a combined noble phantasm, you absorbed the power of three separate ones and used them to unleash an even more devastating fourth noble phantasm."

Y/n: "Huh. Yeah, that'd do it."

Tokiomi helped Y/n to his feet before seating him in front of FemGil's throne.

Tokiomi: "I have to say, that was rather astounding. What manner of magecraft was that?"

FemGil: "Oh shut up, Tokiomi. That was not magecraft. What you witnessed was the machinations of true magic."

Y/n: "Yeah, that's right. True magic mixed with me effectively being the direct reincarnation of Abzu."

Tokiomi looked confused as FemGil shot up from her throne.

FemGil: "EXCUSE ME, REPEAT THAT!?"

Y/n: "Huh? Oh, yeah I'm Abzu's reincarnation. His rings are melded to my ribs and I can use his power."

Tokiomi: "W- Who exactly is Abzu?"

FemGil: "The father of life and the embodiment of fresh water. All rivers in this world flowed from Abzu. It was Abzu who mated with Tiamat to bring forth all life in this world."

Tokiomi: "S- So he's a primordial god!?"

FemGil: "Precisely, at least you don't need me to spell it out for you like usual."

Y/n snickered before feeling himself go faint.

Y/n: "Oh well, looks like I need to recharge for a bit. Drop me off with the others, would ya?"

FemGil: "You're rather presumptuous to be giving me orders."

Y/n: "You've seen what I can do, d'you really want to catch these hands?"

FemGil laughed loudly, in truth, she was interested in what he could really do. But she decided to comply with his request rather than indulge her curiosity. That would come later."

She left him with Irisviel, who immediately took him back to the Einzbern castle. Tokiomi and Kirei went to the Tohsaka manor while Kayneth called Lancer back to him. Waver and Iskandar accompanied Irisviel and the other Chaldean masters back to the Einzbern castle with Kariya and Zerkerlot.

As Zerkerlot returned to his astral form, Kariya ended up spewing out a few worms. Upon seeing them again, Sakura went completely pale and she froze in place. Ophelia immediately turned her away from the creatures as she completely shut down and eventually fainted.

Once Y/n was put into a bed to rest, Ophelia put Sakura in the same bed. She had noticed that when Sakura had her panic attack before the rayshift, she had slept in the same bed as Y/n to recover faster. Ophelia hoped that it would be much the same here, otherwise Sakura would have to go back to Chaldea.

To be sure, Romani had prepared for a return rayshift to Chaldea.

Irisviel sat in the living room with the servants , Kariya and Waver when Ophelia came back.

Ophelia: "They'll be fine. If Sakura doesn't show any signs of a fast recovery then Chaldea's going to rayshift her back. I trust that's okay with you, Medusa?"

Medusa: "That's fine. Sakura's safety is my number one priority. If she needs to be rayshifted back, then I'll ask Boudica and Emiya to prepare some food for her."

Kiritsugu raised his head as the name Emiya was mentioned.

Kiritsugu: "You have another version of me in Chaldea?"

Ophelia: "Not you, I believe Y/n calls him Shirou at times. Shirou Emiya. He's an Archer class."

Kiritsugu: "I see. Shirou, huh?"

Caster Irisviel spoke up to answer Kiritsugu's unspoken question.

C.Irisviel: "Shirou Emiya is the name of a boy you saved in the real fourth grail war. You raised the boy to be your adopted son and he eventually went on to become a counter guardian like you are."

Kiritsugu: "I see. So I adopted someone..."

Irisviel: "So, what's next?"

Ophelia: "Next, we wait for Y/n to wake up. Once he's awake, then we deal with Avenger."

The others nodded as Anubis closed his eyes to sense if Avenger was still in the underworld, surely enough, he was still being held down there.

Anubis: "He may be weak, but when Ahura-Mazda emerges, Angra will increase in power to match his other half."

Anubis kept his concerns to himself as he knew Y/n would be able to pull it off. However he was rather curious about something.

Namely the new power that seemed to be beginning to manifest in Y/n.

Within the magician's mindscape, said power found it's voice as it spoke.

???: "Ξυπνάω για άλλη μια φορά"

End of Chapter.

Next Time: Light of Ahura-Mazda.