The entrance hall of the office building was fairly standard fare for a magical attack under the cover of night: security cameras smashed, receptionist desk overturned, potted plants knocked over, and human blood splashed over various surfaces. The blood was no doubt courtesy of the two dead security guards on the lobby floor and the receptionist. The fact that the receptionist was dangling from a ceiling fan, suspended by her own intestines was, admittedly, a new one for Kayneth. The bites taken out of random objects were also a bit odd. Usually, the mage noted, bite marks were reserved for corpses and such instead of, for example, computers. Other than that, so far, so standard. All the same, best to ready the vial he'd fished from his coat.
Annoyingly for the Archibald head, but unsurprisingly for a knight, this scene was already enough for that useless Servant to start whining. "My lord," Diarmuid said, "We must make the monster responsible for this pay for their crimes!"
Kayneth sighed and massaged his temples. "Lancer, if you will put aside your knightly foolishness for a moment, try to recall that we know very little of the enemy capabilities. Keep Gae Dearg at the ready and ensure we always have an escape route. We don't need to defeat Caster tonight. Merely finding out what she's doing would be enough."
Diarmuid looked appalled at the suggestion, "Milord, we cannot simply allow her to run rampant! Even putting innocent lives aside, magi have a code of secrecy, don't they?"
Kayneth considered this point for a moment while examining the hanging corpse. "Well you have a point there I admit, she doesn't seem one for subtlety," the Clocktower mage said, brushing the dead woman's hair aside with his right hand to examine some carved script on her forehead."'He who lays hand upon the key shall travel under the rules below. At the first twilight, you shall lift the six sacrifices chosen by the key?' An inscribed aria? But it's not a runic script of any sort, it's just English..."
Kayneth spun the vial in his left hand thoughtfully, "Perhaps she's just insane? She wouldn't be the first mad mage, but I can't think of a legendary witch with a taste for poetry for its own sake. It doesn't even seem complete. It mentions rules but-" his musings were interrupted by the sound of crashing from upstairs.
"My lord..." Lancer said with a pleading tone.
"A riddle for later..." the magus said to himself, opening the clutched vial.
"Fervor, mei, sanguis!" he chanted, pouring the contents, enchanted mercury, onto the ground. The resulting puddle expanded and formed into an orb, which bounced and bobbed at Kayneth's side. "Lancer, you go first."
The knight of the spear nodded and headed up the stairs quietly, with Kayneth moving behind him. When they arrived at the second-floor, Lancer shot ahead of Kayneth, running down a hall lined with offices before darting into the fifth room on the right. The magus proceeded more cautiously. True, Lancer's targeting of that particular office, and the subsequent sounds of inhuman shrieks and fighting, signaled that there probably weren't any other enemies on this particular floor, but you could never be certain of that. Honestly, it seemed that even among heroes, only mages showed any sign of proper caution and appreciation for proper analysis. Kayneth supposed that in that sense, he was lucky that Waver Velvet had spared him being saddled with the mad king of Macedonia.
As the mage considered this Lancer stepped back out of the office, uninjured but bloodstained, and dragging a strange body. "My lord, she appears to have more familiars than those golden butterflies we saw at the warehouse district," the lance knight said, dropping the body before the mage. "There were two of these in there, feasting on a pair of dead men."
Kayneth knelt down and turned over the odd corpse. It was rather odd for a familiar: human in overall shape, but so obviously inhuman that it lacked the stealth that humanoid familiars were typically used for. The inhuman nature was as plain as looking at one of The Dead, except instead of a shambling corpse, this appeared to be a particularly well dressed (the clothes reminded Kayneth of the butlers at the Archibald main house), well-built fellow, who happened to have a black goat head and ruby red eyes. And judging by Lancer's claim of maneating and the shrieking, probably not very intelligent. All in all, it gave the impression of rather inefficient creations. Creations who again matched no legend known to Kayneth, despite Casters's obvious European appearance. Well, perhaps she'd simply disguised herself and was actually of Eastern roots. Troublesome, as that would mean her identity would almost certainly remain a secret until she used her Noble Phantasm and his Master's Vision identified it via the Grail System.
Lancer: "My lord, doesn't it seem odd to you?"
Kayneth turned towards the Servant, annoyed to have his thoughts interrupted. "Does what seem odd to me, Lancer?" Mimicking its master's anger, the blob of mercury beside him vibrated somewhat.
Lancer bowed apologetically, "Forgive me my lord, but we are essentially in enemy territory. Caster should have been able to detect us easily from the moment we entered the building, if not sooner, yes we've encountered nothing but these unprepared beasts. Did she depart already, simply leaving these creatures behind?"
Kayneth's brow creased with worry at this. Indeed, the lack of resistance was troubling. Either Caster was luring them deeper inside, trying to get their guard down, or perhaps more tremblingly, had simply abandoned monstrous familiars for any passersby to find. Kayneth looked back down at the goat-man, noting that she did seem to possess a worrying lack of care for the secrecy of Magecraft with these mass murders, so that wasn't impossible. "..Let us continue upward Lancer."
Lancer started to speak his acknowledgment, but stopped suddenly, spinning around while raising Gae Dearg. The result was the lance knight being pushed back slightly as a powerful projectile slammed right into his guard.
At the same time, the blob of mercury surged into action, forming a protective cover in front of the Archibald mage as a similar projectile smashed right into it, sending a ripple through the blobs structure.
Before the mage and Servant could act properly in response, both projectiles flew backward to opposite ends of the hall, revealing themselves to now clearly be some sort of floating stakes. Then, to the surprise of both men, the two stakes flashed with light and revealed... two girls dressed in red tops and strange black and purple skirt/garter combos. The one who attacked Lancer was an angry-looking young lady with long white hair, while the one who had run afoul of Kayneth's Mystic Code, Volumen Hydrargyrum, was a blonde with a pair of curled pigtails and tears in her eyes.
The white-haired one cursed aloud, "Damn it! Seems Heroic Spirits really are as fast as they say."
The blonde, on the other hand, started to cry and whine. "Big Sister Satan, that disgusting old man made me taste some nasty mercury!"
"Who's an old-" Kayneth began, rocketing to his feet before regaining his composure. "I mean, who in the devil are you people?"
The blonde stopped crying. "Huh? We're the Sev-"
"Don't answer that you moron!" screeched the white-haired one, apparently called Satan. "We're not supposed to be revealing ourselves like that."
"B-but the Lady is leaving her calling cards everywhere!" stammered the blonde.
"Don't question orders damn you!" countered Satan irritably. "Furniture like us doesn't have that right, we just do as commanded. And need I remind you, what we were commanded is to gather up the goats and kill the intrudAAAH,"
The strange girl's tirade was interrupted by Lancer suddenly surging forward and attempted a thrust with Gae Dearg, which was barely avoided. Satan's irritation thus upgraded to outright fury, she produced a red sword of energy around her right arm and slashed at Lancer's neck.
Kayneth, for his part, would have normally preferred to take these strange girls alive and intact for questioning and examination. However, discretion was the better part of valor, and with the enemy's full capabilities unknown, there really was only one response. "Scalp!" roared the mage, causing the blob of mercury to produce several razor-sharp tendrils, which all proceeded to give decapitating the blonde a try.
The blonde girl pouted, producing her own energy sword and slashing apart the attacking appendages. She then tried to close the gap and slice Kayneth himself, something the mage barely prevented by simply commanding Volumen Hydrargyrumto reform and fill the hall as a wall.
Kayneth's opponent tried to slice through said wall as she had the appendages, but any cuts made simply healed in this form.
Lancer meanwhile demonstrated Gae Dearg's abilities as a prana destroyer by slicing right through Satan's blade. The woman barely avoided losing her head by transforming into her stake form just before the Servant's blade took her throat.
Unfortunately for said Servant, this meant that his opponent had just enough of an opening to rocket forward and tear through his side. More fortunately, she didn't simply continue forward and try at stabbing Kayneth's back, instead stopping to gloat over Lancer's injuries. "Ahaha! Blocked my first strike by luck, but too stupid to block the second? Not so tough with your hip impaled I bet, stupid knight! Stupid, stupid, stupid, so stupid that any anti-fantasy fool could probably dispell you!"
"You are not a very pleasant young lady," the Irishman noted dryly.
Kayneth was taking advantage of his own opponent's frustrating inability to pass his shield and the other combatant's distraction to review the situation. Lancer had, of course, proven once again underwhelming and gotten injured. Kayneth himself was trapped in a stalemate where his shield couldn't be broken, but an offensive maneuver of his own would be just as futile and require lowering that shield again. Victory may not be completely impossible, but if more enemies showed up, that useless Servant would most likely fall and the Archibald head would find himself quickly following suit. Kayneth decided that he'd have no choice: he'd have to somehow get past Satan and have Lancer aid his escape through the window at the end of the hall.
Lancer had the distinct premonition that he was being underestimated. Most likely because he was being mocked by what appeared to be a teenage girl whose skirt covered everything EXCEPT the front of her underwear for some reason. The spear user sighed and summoned his second, shorter spear, Gai Buidhe, before charging once more at his white-haired enemy, slashing with Gae Dearg as he did.
"Ahaha! You never learn anything," Satan said, transforming into the stake form again... only for that form to be struck dead on by Gae Dearg, which had been aimed at where Lancer predicted the stake form to appear based on his last experience. The transformation was immediately dispelled, causing Satan to reappear with a large gash on her chest, shrieking in agony. Her cries were quickly cut off by a followup stab by Gae Budihe in her heart.
Time stopped momentarily. The stabbing victim contemplated her own end, the dismissive Master was shocked to have his "useless" evaluation overturned, and the blonde sister sensed her sibling's demise.
The world resumed movement. Lancer charged past his opponent, who was already dissolving into golden light and headed for Kayneth's defensive position. "My lord!"
Kayneth nodded and waved an arm, causing Volumen Hydrargyrum to move aside, revealing the twin-tailed blonde to have taken stake form. Just before Lancer could strike again however, she rocketed off down another hallway and out of a window.
Confirming the enemy's escape, Lancer sighed and looked at his Master. "Shall we continue exploring the upper floors, my lord?"
Kayneth contemplated this a moment as he had Volumen Hydrargyrum reform into the blob shape it took while on standby. Then he responded, "No, there could be more of them, and it sounded like they've already finished whatever ritual they were conducting anyway. We shall return to base."
As the two-headed off down the stairs, Kayneth made a mental note to send a familiar to this place and the other massacre site tomorrow morning and examine everything in detail. "Oh yes, and Lancer?"
"My lord?"
"...Good work tonight."