"Huh, when did this happen?" Natsuki Subaru asked himself while soaking in the heated water of the tub he was in inside the Mathers' Mansion, looking down at his belly button.
Or, at least, where his belly button should be. Instead there was a large amethyst-colored gemstone embedded into his navel where his belly button used to be. He poked and prodded at it, even going as far as to try to pull it out, but it stayed taut against his stomach. It felt smooth to the touch and was cooler than his body was.
Subaru hadn't even noticed he had a gemstone on him when he got isekai'd, too preoccupied taking in the sights around him while also trying to get Emilia's insignia back. He shivered in fear at remembering how he got his stomach cut open not once, but three separate times, remembering the pain and agony he associated with the memory. He shoved the thought into the recesses of his mind for the sake of his sanity as he got out of the tub to dry himself off, only to bump into Ram who was holding a towel that he assumed was for him.
"Sorry, I already have a towel, Ram-nee," Subaru apologized, itching the back of his wet head.
"It wasn't for you, Barusu. I had assumed Master Roswaal-sama was taking a bath and went and fetched a towel for his convenience," the pink-haired maid corrected, her eyes trailing over his body, surely to mock him, until her eyes landed on his navel. Her eyes widened a small bit as she asked, "What is that?" while pointing at his gemstone.
"I have no idea. I just discovered it myself a couple of minutes ago," Subaru answered honestly.
"You mean this is new? You have no idea how you got it?" Ram asked, suspicion laced in her tone of voice.
"Nope, I think it's cool though."
"Stupid Barusu, only you would see such a thing as non-worrisome. If I was you, which I'm glad I'm not, I'd go to Beatrice-sama to get it examined," Ram backhandedly suggested, turning on her heels and walking away from her colleague.
"Hey, Beako!" Subaru greeted as he poked in his head through the door. He was wearing his butler uniform, and he thought he looked quite stylish in his new clothing.
"Betty does not like that name, I suppose!" Beatrice shouted, slamming shut her book while wondering how this buffoon kept breaching through her Door Crossing. "Betty is busy, what do you need?" she asked, sitting on her stool in the center of the Forbidden Library, an annoyed look on her face.
"Aw, that's no way to treat a friend, Beako! I came here to say goodnight and wanted you to look at something for me," he said, shutting close the door as he walked further in, stopping a couple of feet away from the great spirit.
"What is it, in fact?"
Subaru wordlessly pulled up his clothing to reveal his navel, which Beatrice looked at with great interest. "I noticed that I had a purple gem on my belly button after taking a bath. I hadn't noticed it until today. I was hoping that you could shed some light on it, seeing as you know a lot about magic," he said, hoping that buttering her up would make her more willing to help him.
"Hmm…" Beatrice hummed as she got off of her stool, getting really close to the annoying child in front of her and analyzing the gemstone with great detail. "It's a purple-colored diamond, I suppose. And it's just stuck there on your stomach, I wonder?" the librarian asked as she crossed her arms, looking up to her uninvited guest.
"Yep, it's been there since…well, maybe a day or two ago," he guessed. "Is it dangerous or anything?"
Beatrice put a hand to the gemstone and poured some mana into it, getting back some results. "It's not killing you, but it is connected to your gate in some weird form or another."
"My 'gate?' What's that?" Subaru asked, a confused look on his face.
Beatrice sighed as she explained while twirling her twin drill, "In simple terms it allows you to cast magic, I suppose. Your element is Yin, dark magic just like Betty's in-fact."
"Woah, that's cool! What can dark magic do?!" the young man asked excitedly, a sparkle in his eyes, completely forgetting his primary reason for the visit.
"Ask someone else! Betty is tired of your presence, I suppose!" Beatrice shouted, raising her hand to not only open the door to the Forbidden Library but to also push the boy out with a powerful gust of wind. The wind came and pushed Subaru out as he yelled comically, getting thrown into a random hallway of the mansion as he slammed against a glass window, cracking the glass and falling to the floor.
The young man groaned as he got himself up, feeling a tad woozy and hurt as he looked at the window. It had a large spiderweb-like crack in the center of the glass window, and it looked like a minor amount of force would cause it to break completely. He noticed that some of the other windows were open, and looking out he saw that it was a long fall to the solid bottom. "If that window wasn't closed I would've died…" Subaru thought aloud, shivering in fear before he reigned himself in, lightly slapping his cheeks to pull himself away from the horror. "Don't think about that! I should find Emilia-tan to say goodnight to her!" he resolved, before noticing that she was outside with a lightshow around her.
Natsuki Subaru made his way outside to the field Emilia was, silent as he approached her. This was because in his first loop he saw her do the same lightshow on their way to the Loot House and back then he interrupted her, scaring off the minor spirits (and earning a tongue-lashing from his crush).
So he stood off to the side as he patiently waited for her to finish, waiting only a couple of minutes.
"Subaru, thank you for being patient. It's good to see you, but how has your work gone?" she asked with interest, her bell-like voice like a healing salve to his overworked soul.
"It's been good, Emilia-tan! Rem-rin and Ram-nee sama have been working me to the bone but I think I'm getting used to it," he answered. "Honestly, it seems that the two of them were already overworked before I came along, since there's so much to do," Subaru admitted, a smile on his face as he looked upwards into the sky. "The moon sure is pretty."
"Yes, it's far beyond our reach," Emilia responded eloquently.
"I got a really touching response without even trying?!" the young man joked as he craned his neck to her.
She giggled as she questioned, "Still, don't you think you're a bit lacking in ambition? Like that time with Puck, and in the capital, when you asked for my name."
Subaru sighed contently as he wagged a finger at her playfully, "You just don't get it, Emilia-tan. I want what I want at that exact moment, and I want it from the bottom of my heart."
"Huh?"
"A couple days ago I could have cheated Ros-chi out of his money, but I wanted a place to stay and money to earn."
"Couldn't you have made yourself a permanent guest then?"
"You're right! I could have totally done that!" Subaru lamented, grabbing at his hair in despair.
Emilia giggled at his dramatic acts before saying, "Still, I want to personally repay you for getting back my insignia. It's reallllly not fair that all you want is to pet Puck's fur."
"Okay, then how about this: You wanna dance?" he suggested, a smile on his face as he asked.
"Oh, um, I'm not a really good dancer," Emilia admitted, a blush on her face. "I've never had someone watch me dance before, well, if you don't count Puck. I don't want you to watch me stumble and fail."
Subaru turned on a song from his flip phone, setting it aside as it began to play music as he covered his eyes.
"How is that music playing?" Emilia asked curiously, cocking her head to the side in wonder.
"It's a special metia I have. I'll explain it later, if you want," Subaru hurriedly dismissed. "But first: Since I can't see you anymore, my lady, may you take my hand?" he asked as he held out a hand in a gentleman's way.
Emilia sighed goodnaturedly as she looked abashed before growing a spine as she knew he couldn't see her. She took his hand and watched him get shocked by her doing as he asked, thinking it was slightly selfish of him as he uncovered his eyes. He grinned happily as he tugged at her, before starting to move in a traditional dance. They walked forwards and backwards, shuffling throughout as they caught on to each other's movements, watching each other's shoes move and step into position. They steadily increased the speed of their impromptu waltz, smiling at their antics.
Eventually Subaru twirled her smoothly, surprising his dancing partner. She audibly giggled at it, liking that she enjoyed this more than she let on. They broke apart from each other temporarily, the both of them doing separate dancing moves as they slowly drifted together, a blush on Subaru's face from the beauty he saw. They came back together before Emilia slipped on the ground. Thankfully the black-haired man caught her like a true gentleman, their faces so close they were doing Eskimo kisses. Emilia laughed nervously before the two of them devolved into chuckles, closing their eyes as a purple light emanated from Subaru's gemstone, encompassing them completely, unknown to them.
"What's going on?" came the confused voice of the humanoid on the lawn. They were wearing a mashup of a butler's uniform and a white/purple outfit that was distinctly feminine. Their face had murky-blue colored eyes with long whitish black hair, while their cheekbones were prominent and their physique strong-looking. Two pairs of shoes were off near their feet and the being reached out to put them back on before noticing their hand, which was not a milky white or pale skin, a mixture of the two. "Whoa. Why is my—Why is…your hand off-color?"
The being trailed a hand up their leg, feeling themselves up as the hand finally reached up to their face before asking hesitantly, "Emilia-tan?"
"Subaru?!" the same voice exclaimed, shocked at what was happening.
The being tried to get up from the ground, struggling to do so as they weren't well-coordinated. "What's going on?!" the being asked before replying to itself, "I have no idea!" They managed to get up to a crouching position before finally managing to get upright. "What is this?" the being asked themselves. "Whatever this is, it's amazing! I feel so much…"
"Powerful? I do too," they responded to themselves, clenching and unclenching their fists, feeling as if they could break boulders with little effort. "Subaru, what are we?" the Emilia part asked, radiating a bit of fear.
"Don't be scared, Emilia-tan. I'm sure this is some weird dormant magic that I'm now just unlocking. It's like we've combined into one being," Subaru hypothesized before commanding the body to throw a punch. It whizzed through the air and felt powerful.
"We have to show everyone," the fusion said, a grin on their face.
"Pretty cool, right?" the fusion asked the group before them, consisting of Rem, Ram, Roswaal, and (surprisingly) Beatrice.
"What is this, I suppose?" Beatrice asked, spinning one of her drills with her fingers. Because of this new person's extra height the being had its navel exposed, revealing the purple-colored diamond that she'd seen on the boy earlier that night. "Wait, are you that annoying boy from before?"
"I have a name, Beako-sama!" the fusion said with mock hurt, adding on the honorific at the end due to Emilia's involvement. "It's Subaru…or is it Emilia? I don't know who or what I am," the being admitted.
"I must saaaaaaaay, I have never seen a situation like this evvvvvver," Roswaal drawled out, looking highly amused. "Emilia-sama, are you truly a part of this weird mixture with Subaru-kun?"
"Yes, Ros-san!" the fusion responded, again mixing the two names together. "Subaru and I feel like we're one person, and it's getting easier to do simple things," the being explained. "I have no idea how this happened."
"Of course you wouldn't know, Barusu. It's probably that," Ram pointed at the fusion's navel, showing that they didn't have a belly button but a purple diamond instead. "You did, or at least Barusu, tell me about it earlier today. Maybe that's the cause of this…weird amalgamation of a person."
"Beatrice-sama, can you analyze this new person to get a gauge of them?" Rem asked, finally entering the conversation. Secretly, the combined being smelled like both Emilia and Subaru, with a hint of the witch's scent, which was odd but since it wasn't overpowering she elected to ignore it for now.
"Hmph, fine, I'll do it," Beatrice agreed, approaching the tall individual that was easily 6 feet tall and did a bit of spellwork on the fusion. "They appear to have a larger than average gate, and they have the affinities for both Fire and Yin magic, much like the silly girl and the annoying ant respectively," she ignored their squawk of indignation as she drained their mana to assess their potential to being an enemy. The fusion vibrated violently and took the mana draining like a pro, managing to remain standing, though heavily tired.
"Did you have to do the mana-sucking thing again?" the combined being asked tiredly, resting their hands on their knees as they breathed in and out like they just finished a marathon.
"That's a horrible name for that, I suppose! I'm a little impressed that you're still standing, unlike last time," she back-handedly complimented before turning towards the lord of the mansion. "They're safe to be around, and they are who they say they are: A weird mixture of the silly girl and the annoying ant."
"That puts my miiiiiiind at ease. Thank you, Beatrice-sama," Roswaal thanked, bowing slightly to the great spirit. She "hmphed" as she approached one of the doors of the mansion, using her magical powers so that the door opened up to her library instead of the original room. Beatrice left them, leaving Rem, Ram, and of course Roswaal. "It's getting laaaaaaaate. How about we reconvene at breakfaaaaaast?" the clown asked, using hand gestures to tell his staff to go back to their rooms.
"Sounds like a good idea! We're feeling tired from all this," the fusion said as they yawned, scratching their head as they departed in long strides to Subaru's room. They entered and immediately fell back-first onto the bed, splaying themselves on the mattress. "This was certainly…interesting."
"I'd say it was cool!" the Subaru part of the fusion enthused, making imaginary snow angels in the comforter, loving the feeling of everything. "It's cool to hear each other's thoughts and stuff!"
"Do you think this is permanent?" the voice asked themselves in a worried tone.
"I'm sure everything's going to be alright, Emilia-tan! But before we go to bed, we have to decide on a name for ourselves."
"True; I agree, but what should this person's name be?"
"I don't know, but we'll figure it out. We have all night, after all."