BEGIN: PROLOGUE

A door opens, and someone meanders through, taking off and setting aside their shoes, dragging their luggage along into the living room. He sits down, the couch reacting to the sudden pressure by letting off a small cloud of dust.

With a soft thump and a longing sigh, I fully sank into the comfortable couch, taking a glance at the rather mundane surroundings of my apartment. It was mostly average, quaint, and cozy, suited towards a single occupant, a small antique clock hung on the wall ticking, modern furnishings covered with a thin layer of dust, and some small knickknacks adorning the tabletops. My bare feet lay comfortably on the cold hardwood flooring, running over the minor imperfections in the wood.

I got up, and with a swing of my arms, the curtains leading to the window split open, fluttering in the air unveiling the scenery. I focused on the rather familiar view outside of the open window, numerous light pink trees in the distance, interspersed with tall concrete buildings, obscuring the nature that laid past the man-made constructs. The sky was a vibrant orange, the sun transforming into a mere half-circle on the horizon. It was around 6:45 PM when I entered the apartment, flying from America always made me feel slightly jetlagged.

It's good to be back home… for how long, however, I did not wish to tempt fate with my questioning. Fiddling with the small necklace around my neck, I gripped the centerpiece, having grown rather accustomed to its shape in the grip of my fingers.

The main jewel was a vibrant cyan oval made out of some magic stone I never bothered to ask my superiors about. It was surrounded by a crossed mesh, a blue cage delicately holding the treasure, surrounding that was a border made out of a silvery-gray metal, featuring delicate carvings and arrayed in a vague arrowhead shape. Two crimson tassels hanging off of the furthest ends and swaying in accordance to my slight movements, and a string pushed through two holes, forming a loose formation to cling softly to my neck. Foreign markings adorned the crystal in the middle, in a language incomprehensible to my mere mortal mind and… an odd warmth emanating from the gem. A temperature difference that felt like it caressed me, comfortable and safe.

The necklace was one of the gifts I was given shortly before I departed from the Chaldean headquarters and returned to civilian life, though a brief one-year stint in the United States added contrast to the otherwise unexciting trip back home.

"As if returning to who I was before was possible," I ruminate aloud to myself…

"Senpai? Is something wrong?", the image of a pink-haired girl flashed in my mind as I stared at the large ornate shield that hung on my wall, though only a replica, it was massive, heavy, and incomprehensible for a normal person to hold, or even swing around, I quickly looked away, not bothering to take in any of the more fine details of the shield, too many memories.

'Better do something worthwhile if I am going to spend the rest of the day here at least,' Though my knowledge of magecraft was 2nd-rate at best, strict tutoring from the staff back in Chaldea assisted in forming a basic framework to at least keep myself alive in the situation the Mage's Association ever got the bright idea of slapping a Sealing Designation onto me. Placing some runes on the ground, a small bounded field was soon created, though only to conceal the prana within and stop anything unnatural from leaking out.

With a swift swing of my arms, a small portal opened up in front of me. It was a doorway to a place I would call my "storage dimension" otherwise known as the Archive, something involving imaginary number space and other concepts that flew over my head, I was a field operator not a researcher for Christ's sake. The only reason why I was able to access it in the first place was an organization-wide effort which included most of the Casters doing something to the system. A final gift that was given to me for my service so to speak. Taking a quick catalog of my items, I brought out a hot steaming bowl of mapo tofu, soon digging into the only food located within my apartment…

SHIT! OH MY GOD, IT WAS SPICY! The only taste that inflicted my poor tongue was pure spice, a fiery death, forcing me into a full bodily flush as I tried my best to gulp it down before it set fire to my very soul. I was gasping for breath and hoping for relief from the torture, nearly keeling over and passing out and chugging whatever liquids I could get my hands on.

How in the hell Amakusa dug into these things like candy I will never find out, he did mention it was something pseudo-inherited from a father figure of a Grail War long past that managed to carve itself into the Throne of Heroes and even his spirit origin, even Rasputin shared the same palate so maybe it was tied to the Kotomine name or something.

The damned summoning system kept pumping those things out so when rations were low, mapo tofu swiftly became a part of the diet, something even I begrudgingly started liking after my… 56th bowl. The damned system had a hardon for the priests, black keys took up at least half of the space inside of the Archive and if I had a nickel for the number of pictures of a shirtless Rasputin, I would have at least a dollar.

I passed out soon after that, probably from the spice, but I like to think it was from exhaustion from traveling.

X✦X

After waking up, I soon found out that the night passed swiftly by, and I was left in a cold sweat from sleeping on the table. I could thank the tofu for one thing though, it replaced the usual nightmares with spice and pain.

A long shower was on the menu to scrape the remnants of dirt that accumulated after my previous washing and tend to other hygiene-related issues. I put on the Anniversary Blonde outfit, which consisted of a black vest, blue tie, white dress shirt, and blue dress pants when I was finally cleansed. Overall, I was probably overdressed for casual occasions, but it was the best choice I had other than school uniforms.

Though it only took a short while to clean off the dust that accumulated in my room and take special care of the mecha figurines in the display case, I decided to go take a quick stroll around the city. Though I had no final destination other than returning later, some physical activity couldn't hurt that much. All I had on my itinerary at this point was to get home by midnight and perform a certain ritual. Though it was only theoretical, tonight was the night that presented all of the ideal conditions needed.

The amulet started glowing softly in response to my thoughts, its blue light piercing through the fabric of my clothes.

X✦X

It was 2:00 PM at this point, having spent around three hours just meandering around the city, taking in familiar sights, and admiring how much the city could change… or how little it did change since I left. As I passed near the local library, I felt something resonate in my right hand. A thaumaturgical signature in the library started pouring out prana and triggering every red flag in my mind.

My right hand started burning. Though faint, the scars of my time in Chaldea were still visible and something in them was reaching out towards whatever was in the library. There were only so many things that could trigger a reaction from Command Seals and I was sure as hell not going to wait until something went sideways.

'A Grail!? Who the hell would leave something that important just sitting in a public library, are they trying to get exposed?!'

I pushed open the doors and ran in, gaining some rather annoyed looks from the librarians nearby, and took a quick analysis of my surroundings.

'No bounded fields, nothing other than that mass of mana just oozing into the air.'

"OW!"

I doubled back towards the voice and soon stumbled upon a… regular-looking guy holding a book… 'What an odd… Grail?'

"Yo! Are you alright over there? I heard someone yell," I started explaining in a calm voice.

"Oh yea, I'm fine this book just fell on me, and… come check it out with me if you are gonna be standing nearby, it looks kind of odd in the manga section doesn't it?"

I sidled over to him, and read the title,

The Weapons of the Fo- Saints

The fifth word seemed scratched out, but I didn't have time to analyze it before he started flipping through the pages.

"This looks like a really old book… is it a fantasy novel? Let's have a look…" As he explained the contents of the novel, the major bits were that another world needed saving from a calamity, so they decided to summon forth heroes from other worlds.

'How familiar… maybe that's the reason the marks on my hand started reacting, another summoning device perhaps? The man in front of me didn't seem magically inclined so there was a small chance he was involved'

"Ugh… this is a premise that's been way~ overused, some average isekai or something… besides a 'Shield'...? Shields aren't exactly weapons you know."

"You know, you may say that but I knew a person who could hit with the 'back of the blade' of a shield."

"How do you even-… never mind," The man kept flipping through the book, even though some damaged pages in between some of the key parts, eventually landing on… "Why's it blank…?" The latter half of the book was empty, nothing in the pages except for the warm color unique to aged books. The next couple of moments were a blur, both of us tipped over and fell? Ah damn, more magic bullsh-

"Ouch!"

Hell YES, 10 points to me, who ate shit right onto the stone! As I sat up, I noticed that we were flanked by 3 others and the person I was with now had a basic-looking metal shield attached to his arm, a green jewel peeking out from its center, 'How ironic, he has a shield after discrediting it earlier…'

I quickly inspected myself and uncovered a gold deck of cards in my hands resembling the class cards that the FATE system repeatedly spat out at me, with the first card of the deck having a cyan gem embedded into its center, the color of my eyes.

My hand started heating up, I gripped my right hand immediately, a flash of searing pain- the Command Seals on my hand started reforming themselves, the scent of burning flesh permeated the air, 'ah how nostalgic~ I remembered the feeling the first time I got dropped into the Fuyuki with Mashu…'

The ambient mana of this place was almost drowning, it was reminiscent of Babylonia, although slightly denser, a magus would have had a field day here but that was beside the point at this moment in time. The dense atmospheric mana was perfect for what I was going to do later.

The pain quickly eased, as I heard the others near me expressing their surprise with being summoned, my thoughts being interrupted by speakers shouting at the top of their lungs,

"OH SAINT HEROES OF OLD! PLEASE HELP SAVE OUR WORLD!"

END: PROLOGUE

Author's Note

Honestly, It's gonna be my first time writing something like this so, if you want to give me critique, do it, I need it. My understanding of both of these world's concepts I think is decent, but if someone wants to correct me on anything glaringly obvious then I welcome it.

There will probably be spoilers to both series, especially Shield Hero because I do intend to go past the Anime if I commit to this fic. Some servants might appear, but no OC ones, I am 100% not good at creating original characters.

Chapters will be however long I want them to be and come out whenever I want, but I will try my best to get them out every so often.