Disclaimer: I still don't own anything.

Grand (Kamen) Rider in Chaldea

Chapter 6: Deductions, Summation, Testing

Due to how dark his room was, Ritsuka had no idea what time it was when he woke up. What he did know was that he was alone. That didn't surprise him.

Lazily getting out of his bed, Ritsuka decided to get ready for the day.

Ritsuka hummed a happy tune to himself as he made his way to the cafeteria along with Mash. On her shoulder was a small, fluffy, white mascot charact… Uh... Team pet. Yeah, let's go with that.

"You're in a good mood this morning, Senpai," Mash commented, noticing the cheerful smile on Ritsuka's face, "Did something happen?"

"Fou!" The mascot char-pet, I mean pet, cried before jumping ship and leaping onto Ritsuka's shoulders.

"I'm just trying to take things positively." Ritsuka tried to justify his current attitude as he petted Fou. Yup, that was definitely it. There was absolutely no other reason, "Because I know someone's going to ruin it soon…"

And by someone, he naturally meant the newest Servant in Chaldea.

"Oh yeah. That dream." The smile on his face was swiftly replaced with a confused frown.

"Senpai? What's wrong?"

"Hmm? Oh, nothing." He should ask Decade about it first. For all Ritsuka knew, that memory might be something the Servant wanted to keep a secret although he doubted that it was.

Eventually, the two (plus Fou) arrived at their destination. And were instantly met with what could only be described as…

"Borrowed."

"Stolen."

...Actually, they had no idea what to call the scene. An argument? A debate? Without any context, it was hard to put the right word to whatever Decade and Merlin were arguing about. The two were sequestered to their own table as they continued arguing.

Also, without any context, it was difficult to figure out why Decade was wearing a formal black suit and tie. Because he was wearing one.

"Borrowed," Decade said.

"Stolen," Countered Merlin.

"Borrowed."

"Stolen."

Despite how out of place it was, the scene of a wizard and a waiter arguing wasn't attracting that much attention. Everyone else merely ignored the two in favor of going on with their morning schedule.

"Oh, Master, Mash, good morning," Emiya had noticed their entrance and greeted them

"Good morning, Emiya," The two greeted the Archer Servant in turn before going to find a place to sit.

"Borrowed."

"Thank you for the meal, Emiya."

"It's nothing," Emiya replied.

"Stolen."

"...So what are they arguing about?" Ritsuka finally asked after watching the two for the last 15 minutes or so.

"Borrowed." "Stolen."

"Nobody knows," The Archer Servant admitted, "They've been going at it since I came in."

"I see… Hey, Fou."

"Fou?"

"Can you keep Merlin busy?"

"Fou!" The small animal didn't need to be told twice.

"Borrowed."

"Stole-!" "Fo! Die, Merlin!" "-Ack! Cath Palug?!" Merlin was cut short by a kick to the face by Fou, sending him tumbling to the floor.

"Finally," Decade let out a sigh of relief as his argument with the wizard finally ended. That moment didn't last long, however, as he noticed exactly what had attacked Merlin, "That is..."

"Hey, Decade. Good morning," Ritsuka greeted the Rider-Class Servant as he and Mash came over.

"Oh, Master."

"There's something I want to ask yo-"

"Before that," Decade interrupted his Master as he gestured to Merlin, who was currently trying to wrestle Fou off of him, "Do you know what that thing is?"

"That thing? I mean, Merlin is part incubus but I don't think you could call him a-"

"Not him," Decade interrupted Ritsuka again, grumbling, "I'm talking about Prima- I mean, Four or whatever you call it."

"You mean Fou?" Mash asked, "You know he is?"

"It's a pain in the ass, that's what it is," Decade said with an annoyed tone, "Why do you still have it running around here?"

"Fou is just…here. He's always been with us." Mash answered, a bit upset at what the Servant had called Fou.

"I know it helped you two in the past, especially you, Shielder," Decade warned the two, "But be careful around it."

"Hold on a minute. Exactly what are you trying to say here?"

"What was that thing you wanted to ask me about?" Decade ignored the question directed at him, "If it's about what me and that wizard-" "Stop it already, Cath Palug!" "-was arguing about, it's borrowed, not stolen."

"No, not that." While he was curious about that and what he had meant about Fou, Ritsuka wanted to know about the dream first, "Last night, I had a dream about you."

"Having dreams about other Servants? What would your girlfriend say?" Not wasting the chance, Decade immediately started teasing his poor Master.

"Wait-! I didn't say- I mean, I don't have a-"

"Yeah, yeah, whatever you say." How he was ever able to keep it a secret was beyond him, "What was it about?"

"Well-" "Oh, wait. I just remembered, there's something I need to do." Immediately forgetting that his Master wanted to ask him something, Decade stood up and left the room, walking over the still wrestling Merlin while on his way.

"Guess he was no longer in a talkative mood," Ritsuka sighed, "Hey, Mash, what else is on the agenda today? ...Mash?"

For a (not so) inexplicable reason, his kouhai was giving him a strange look.

"Uh… What's wrong?" Ritsuka asked, not realizing why Mash was staring at him, "Is there something on my face?"

"No… It's nothing…" For totally and completely unknown reasons, Mash didn't seem to be answering honestly.

"Are you sure?"

"Yes, there's no need to worry about me," Mash timidly smiled.

"If you say so…"

"Anyway, we should visit the infir-" *BANG* Mash's suggestion was cut off by the poor cafeteria door flying open, revealing Da Vinci.

"There you two are!" The Rider-Class Servant shouted as she spotted the two she was looking for and running up to them

"Da Vinc-" "No time to explain! C'mon!" Da Vinci impatiently grabbed the two's arms and dragged them out of the cafeteria.

"Hang on! Wait for me!"

Control Room…

"I'm back!" Da Vinci announced her arrival, still dragging Ritsuka and Mash around. Behind them, Fou was sitting on Merlin's shoulder as the wizard followed the trio.

From the current state of the Control Room, it was obvious Holmes and Sion had been busy with their investigation. Sheets of paper covered the floor around the center of the room along with several half-opened books.

The two were discussing something near the center of the room, right in front of several whiteboards with pictures of Decade on them. Upon hearing the four (and Merlin) enter, they immediately went to business.

"Good. We can finally get started," Sion's voice sounded weak like she had been talking for hours.

"Do you finally manage to figure out his True Name?"

"For that, you would have to wait until the end." Holmes deliberately kept their final deduction a secret, "Miss. Sokaris, why don't you do the honors and begin."

"With pleasure," After taking a moment to clear her throat, Sion took a stick from her pocket and tapped one of the whiteboards with it, "As you all can see here, the point of me burning the midnight oil is to discover the true identity of Chaldea's newest Servant."

"And did you?" Mash asked.

"We'll get to that," Sion told the Demi-Servant before continuing, "As we all know, the name he had given us is most likely an alias with the reason for him hiding his True Name currently being unknown. What we do know is that thinks he is a Grand Servant, and his Saint Graph does reflect this somewhat."

"But his Saint Graph has been messed with," Da Vinci interjected, "It is currently unknown who tampered with it. At the moment, we are unsure whether or not Decade's original and untampered Saint Graph would actually be that of a Grand Servant's."

"So he might not actually be a Grand Servant?"

"Precisely," Da Vinci nodded, "And-"

"And thanks to Ritsuka's account, we know he is able to change his Class and use the abilities of other Servants," Sion stated, "The current list of known Servants are Thomas Edison, Miyamoto Musashi, Robin Hood, and presumably Billy the Kid. Also according to Ritsuka's account, Decade using those powers is not his Noble Phantasm."

"This is getting rather long," Merlin mumbled as Fou lightly punched his cheeks.

Ignoring Merlin's complaint, Sion continued without missing a beat, "Additionally, these powers belong to a presumed-to-be-Servant known as Ghost. Once again, we have no clue as to who Ghost is or why Decade could use them.

"Assuming that the armor you described is a Noble Phantasm, it is likely the original owner of the armor is Ghost," Da Vinci told them.

"Moreover, a borrowed Noble Phantasm is weaker than it should be. Decade managing to defeat three Servants using it implies that Ghost would be a high-ranking Servant. Unfortunately, that is all we were able to gather in regards to Ghost."

"You've been talking about Ghost more than Decade at this point."

"Fou, if you may so please, kill Merlin."

"Fou!" "Ahh!"

"Back to the subject," Sion spoke as if she had not just ordered a hit on the Caster, "From what we are able to understand, there is a 99% chance that Decade is from a Parallel World."

"...Why didn't you start with that?" Ritsuka couldn't help but ask.

"Our first evidence of this is one of Decade's Class Skill; Traveller of Worlds," Sion tapped a piece of paper that had been taped to one of the whiteboards, ignoring Ritsuka's question, "If the name is of any indication, it means Decade is not originally from this World and could cross into other Worlds, similar to Arthur Pendragon and the female Miyamoto Musashi that Chaldea had encountered."

"Holmes had theorized that unlike them, Decade could control when and where he wants to go and can take whoever he wants with him."

"Wait, you mean that warehouse yesterday was-"

"It's just a theory at the moment," Holmes spoke up for the first time, "But we're assuming that you along with the other three were brought into a Parallel World."

"Just like that?!"

"As I said, it's just a theory."

"Our second evidence is Merlin's first meeting with Decade." Da Vinci took over the explanation again, "According to him, Decade had appeared in several different Avalons in search of someone named Yuri."

"Our third and final evidence is thanks to LAPLACE," Sion said, "There are no records of anyone named or with the alias of 'Decade' in our World's past. In other words, he doesn't exist here."

"In conclusion-!"

"You haven't figured out his True Name." Mash deadpanned.

"...no, we haven't."

"All of that and all you have to show for it is a dirty room? For sha- Ow! Stop it, Cath Palug!"

"Well, that wasn't useful..." Ritsuka sighed.

"Sorry, but it was best you knew that Decade wasn't from this World," Da Vinci said, "Holmes was against telling you about it until we had more information on Decade's identity, but Sion and I thought that this couldn't wait."

"And you two can't just outright say, 'Decade is from a Parallel World'? Did you really have to go all out like that?" What was even the point of all that?! (Padding)

"Is there anything else we need to know?" Mash asked, equally annoyed as Ritsuka.

Sion shook her head in response, "Nothing yet. His last Trait is still hidden, or rather we haven't seen anything like it before."

"His last Trait?" That confused Ritsuka, "I thought we didn't know two of them?"

It was at that moment everyone else in the room (minus Merlin) realized that Ritsuka was still in the dark about that Trait. Mash, meanwhile, had learned about it during the previous night from Holmes and Da Vinci.

"Did we forget to tell you? That's our bad, really." Holmes apologized, "We managed to discover one of Decade's unknown Traits yesterday. We meant to tell you this, but then you had to take off before we could."

"So? What is it?"

"Decade is a Threat to Humanity."

"...So he actually is a Foreigner in disguise!"

"..."

"..."

"..."

"..."

"...Why are you all looking at me like that?"

Noon…

The rest of the morning went by quickly. After the...revelation in the Control Room, Ritsuka did his daily activities (read: grinding) until it was finally time for lunch. That was when problem decided to rear its ugly head.

"There you are," As soon as he stepped foot out of the simulator, Ritsuka came face to face with Decade. The former had stayed back to shut off the simulator so he was by himself, "There's something I need you to do."

"Uh… Decade? What are you wearing?" Once again, the Servant had a brand new, yet still odd outfit. This time, he was wearing a postman's uniform.

"This? Don't think too hard about it," Decade didn't bother answering him at all, "Right now, there's something more important than my clothes changing."

"O...Kay? What's this important thing you're talking about?"

"I'll get to that. First, I need you to get some Servants. Just three would do, no more, no less," Decade ordered him, "I'll be waiting inside the simulator."

"...What?"

"Hurry up and get me some punching bags already. I need to check if that Noble Phantasm works correctly or not." The Servant then entered Chaldea's Simulator, leaving his poor Master thoroughly confused and exhausted.

"...What?"

It didn't take Ritsuka that long to convince some of his Servants to fight against Decade. Actually, he didn't need to convince them at all. In fact, the problem he ran into was choosing who would be Decade's punching ba- Er… Battle partners…

While there were many, many Servants who wanted to volunteer themselves to be part of this little experiment, Ritsuka had chosen three who he thought would be able to handle whatever Decade plans to throw at them. Now, the four of them stood outside the simulator.

The first chosen candidate was the Rider-Class Servant and famous Greek hero, Odysseus. Decked out in his Aigis, complete with its vaguely snake-shaped helmet, he would certainly be a good match against Decade.

Second in line was Mysterious Heroine XX, or just MHXX, a Foreigner from outer space (and another universe). Currently in her 1st Ascension, she wore the high-tech armor Avalon and wielded a spear.

Finally, the last of the three chosen warriors was- "Why was I chosen?!" -complaining loudly.

"You're here because we needed a Support Servant," Ritsuka answered the question like it was obvious.

"Then why not El-Melloi or Scathach-Skadi?! Even Altria could do this instead of me!" Even if he can't see the future with his Clairvoyance, Merlin knew that his new "friend" wouldn't hesitate to kick him in the face if given the chance. That chance would be in about 30 seconds, give or take 5 seconds.

"That's because…" Ritsuka had a serious look on his face as he answered Merlin.

"Because…?"

"...you skipped out on practice just now."

"Oh…" He did do that, didn't he? "...Can I skip out on this one too?"

"No," Ritsuka bluntly said.

"Fujimaru… No, Master," Merlin had a grave tone to his voice, "You're forgetting one important detail; I am a Caster...and Decade is a Rider! I'm not going to last 10 seconds against him!"

"You're exaggerating," Although a part of Ritsuka knew that it wasn't that big of one.

"Merlin," Odysseus interjected, having gotten sick and tired of the Caster's whining, "Stop wasting our time. The sooner you stop talking, the sooner this will all be over."

"That's easy for you to say!" Merlin pointed at the Greek hero accusingly, "You are a Rider too! His attacks aren't going to be as painful for you as they would be for me!"

"Merlin, you're forgetting about something," Ritsuka defended Odysseus, "Decade's first Skill will be painful for Odysseus."

"Oh… Right…"

"Will you stop this already?" This time, it was MHXX who was grumbling, "It's already lunchtime. I'm missing out on the Chief's cooking!"

"Hmm? Is that really the only reason?" A mischievous grin suddenly popped on Merlin's face, "Are you sure that it's not also because you want to impress Fuji- Ow!"

"Oops, my hand slipped," She says that, but MHXX didn't sound apologetic at all.

"Come on, Merlin. This will be over soon." And it'll most likely end with Merlin in a full-body cast.

Finally, after prodding Merlin, they entered the Simulator, set to the streets of non-descript city #394 (nighttime) setting.

"Great," Decade likes to fight in an urban environment, Ritsuka guessed, "Now, where is-"

"Watch out!" Odysseus reacted quickly and parried the blow that was aimed at Ritsuka.

"Master, stand back! Engaging the enemy!" MHXX declared as she attacked their opponent with her spear, aiming for his chest.

Their foe, however, simply took the attack head-on, sparks flying off of his armor. While he gave no indication of actually being harmed by the blow, their opponent did step back and put some distance between them.

"Decade, be careful! You nearly… Eh?" Ritsuka tried to reprimand who he thought was Decade for his carelessness until the Master saw exactly who had attacked him, "...Odysseus, you don't have a brother, right?"

"No, I do not." Had the Rider had not been wearing his helmet, everyone could have seen Odysseus glaring at the person before them.

The person standing before them wore armor that looked eerily similar to the Aigis, the general shape at least. Color-wise, their attacker was mostly purple with silver and gold accents and had a black undersuit, seeing him apart from Odysseus' black and silver color scheme.

Similar to Odysseus', their enemy's helmet resembled a cobra's head with three pairs of black ridges acting as a visor. His mostly purple chestplate was slim and wide, with pointy, silver shoulder pads and two golden hexes in between them. Finally, there were various silver circular pieces all over his body. In the man's hand was a long, spiral sword.

"Decade…?" Something told Ritsuka that he was wrong. Maybe it was because the man reminded Ritsuka of Beryl or how the Servant(?) looked like he was about to attack him again. Regardless of the reason, Merlin shared his sentiment.

"No, that's not him," Said the Caster, "Look at his belt."

The man's belt was completely different from Decade's. Unlike the pink belt buckle Decade had, their attacker's belt buckle was rectangular, the same shade of purple as his armor, and had the symbol of a golden cobra on it.

"Who are you?" The man didn't answer Ritsuka's question.

"Whoever you are, attacking our Master is not something that would be taken lightly," Taking their combat stance, both Odysseus and MHXX prepared for battle.

"Hmm… Something's not right here," Merlin, meanwhile, had a sinking feeling in his stomach. What was it? "...To your left!"

His warning came just in time as MHXX was quick enough to block the fire blast that was sent flying her way with her spear.

"Who's there?! Show yourself!" The Foreigner demanded and, surprisingly, their second assailant obliged.

Stepping out of the shadows was another armored Servant(?). He had a black undersuit with red, blue, and golden armor. His helmet was ornate with two fang-shaped visors and a miniature star map in between them. On either side of the helmet were golden symbols that Ritsuka was unable to see from his spot.

The rest of his armor was similarly ornate, decorated all over with blue orbs to imitate stars and multiple golden bands adding to the wealth of the suit. Additionally, what looks like a large gyroscope was implanted into the center of his chest piece along with his shoulderpads.

Finally, his belt was red, blue, and gold just like his armor with a crank attached to the right side of the buckle. Inserted into the center of the belt was a pair of small bottles, one red and the other black.

"Another one?" Just like Merlin, Ritsuka had a sinking feeling upon laying eyes on the figure in front of them. Momentarily letting that feeling slide, he barked his orders to his Servants, "Odysseus, handle the purple one. MHXX, you deal with the other one."

"Affirmative," "Roger!" With a nod, the two went to engage their assigned targets.

"Merlin, do your best to support them!"

"Ow! No need to shout, Fujimaru, I'm right next to you."

"Hurry up!"

"There's no need to rush," Merlin complained as he conjured his copy of Caliburn, "Besides, I have my own opponent to fight. You really should have chosen an actual fighter, Fujimaru."

"There's another one?" Despite frantically looking around, Ritsuka was unable to see the supposed third opponent.

"I would assume so, seeing as Decade asked for three Servants specifically," Merlin closed his eyes, focused on finding the third, "...And there he is."

As soon as he uttered those words, a completely black figure landed on the ground in front of them. And by black, the figure was literally as dark as a shadow, making it hard to see any distinguishing features. The only way they had even noticed the shadowy figure was due to the shining, silver sword it was wielding.

"A sword of light?" That was the best way to describe the sword, as it illuminated the area around it.

"A Saber or an Assassin then," Merlin let out a sigh of relief, "That's marginally better for me."

A/N: After nearly 3 years of service, my laptop charger has finally given up on me. And because of that, this and future chapters may have more errors than usual because I first wrote on mobile before editing on my laptop. Until I get a new charger, I'll have to do both parts on my phone so typos and such may or may not be more prevalent. This part is being added after the editing process. First off, IMPORTING FILES USING MOBILE SUCKS! Second, EDITING ON MOBILE SUCKS!

So now to things relating to this chapter. Last up, we have three Riders being summoned through you-know-what because I'm throwing another thing in the air and seeing if it sticks. On a side note, what do you think Ouja's Class would be? I'm not asking because I'm still trying to decide it myself. Not at all.

And in Rider news, I've got to say, Xross Saber looks much better in action than in still photos. The debut fight looks amazing and that shot of the Seikens in space was simply spectacular! Also helping the debut was the song, "Revising the Story" (I'm pretty sure that's the name). While "Now is the Right Time" is catchy, Xross Saber's song is much better than it. Also, I can't be the only one who noticed that there were seven books destroying the world, right?

As always, please review and give me some (not-so) well-earned dopamine.