Disclaimer: I do not own Undertale. I own my OC, Aria, but nothing else. All credits for Undertale goes to Toby Fox.

A/N: A day late! Sorry about that, university sucks and I'm only three weeks in. Damn, can't wait for semester break. Anyway, I saw more followers & favourites so thank you so much for all the readers :) I appreciate it!

Enveloped in Darkness

Aria couldn't sleep. By the time the sun has started to rise, she was reading one of the textbooks from the bookshelf. Sans, also barely having slept, opened the door to find the young girl immensely absorbed in a thick, hard covered biology textbook. Her amethyst orbs were scanning in a consistent pace; she was a fast reader. Unable to interrupt the kid, Sans slowly closed the door –

"YOU'RE AWAKE!" – almost to jump from Papyrus' loud voice and sigh exasperated. The human was, however, still captivated by the mere textbook. Toriel, yawning and still in her fluffy pyjamas, stopped at the sight of the young girl studying biology at 6 in the morning.

"My child, are you feeling well?" The goat monster smiled genuinely as she placed her hand on the girl's shoulder, only to gasp and quickly take her hand off. That did the trick. Fear in her eyes, the girl recoiled and snug back under the blanket, quietly whispering,

"Please don't touch me." Toriel, clearly shaken by the incident that happened only a few moments ago, knelt down and gently murmured to the girl under the blanket.

"Are you still ill?"

"…No, I'm feeling much better. Thank you." The hesitant and timid voice of the child seemed to melt Toriel's heart.

"Would you like to eat anything?"

"I'm okay, but thank you."

"I CAN COOK YOU SPAGHETTI, HUMAN!"

"Shh, lower your voice! Frisk is still sleeping!"

"And King Fluffybuns too." Undyne walked in with the yellow monster, grinning mischievously. Toriel blushed furious red and the girl poked her head out from the blanket.

"Hello there."

"Looking better, punk. How's your guts doing?"

"Better. Thanks for asking." Undyne seemed to be taken aback at the genuine smile from the girl. Alphys took her glasses off and nervously cleaned it using her lab coat. Aria noticed the jumpy monster and gave out a gentle laugh.

"You don't have to be so nervous, Alphys."

"I – I… O-ooh, I'm r-really sorry, I d-didn't mean to…"

"…I don't want you to feel uncomfortable. Please, it's okay." The gentle tone of the girl seemed to relieve the yellow monster. Undyne patted Alphys affectionately and her cheeks tinged with red.

"Toriel, I-" the girl's voice cracked, and she hastily coughed to hide it. Toriel's ears perked up at the mention of her names and eagerly nodded to the girl.

"What is it, dear?"

"I'll leave as soon as I recover. I promise."

"But-"

"BUT HUMAN! NOT SO SOON!" Aria grimaced at the loud voice of Papyrus, but shook her head slowly.

"I can't stay at one spot for too long."

[Why?] Frisk had entered the room, signing. Aria opened her mouth, but couldn't say anything.

"…I-"

[If you don't have a specific reason, you should stay with us. You saved the powerless monster and I like you.] The blunt, straightforward method of communication that Frisk used made the other girl smile gently.

You are just the same. And for that, I can't help loving you.

Blinking back the tears that were threatening to show, Aria smiled brightly. The raven-haired girl extended her hand to the child who was taller than her. Frisk gave a small smile as she gently held her hand.

"You can walk!" Frisk yelled in glee as she spotted the petite girl standing in front of the school. The children around her ogled at the girl wearing stripes, surprised to hear her yell for the first time. Aria laughed gently as Frisk jumped into the older girl's arms, smiling brightly.

"It's been about two weeks since it happened. Of course I'd be up and about."

[I'm so glad! Does that mean you'll be coming to school with me?]

"Well… I'm technically a university student, so I'm not too sure, Frisk. Should we go back home now?"

"But mum-"

"She told me that she has to prepare things for class tomorrow so it's my job to escort you, my lady." Grinning playfully, Aria half-kneeled in front of Frisk, her hand extended out for the younger girl's hand. Giggling, Frisk held her hand out in sombrely manner, earning a soft chuckle out from the kneeling girl.

"Shall we?"

"I don't see why not."

"What shall we do with your studies?" Toriel asked, earning a slight grimace from the violet-orbed girl.

"It's okay, Toriel. I…"

"It is not okay to ignore about your education." Aria sighed at her stern voice. She wouldn't be able to keep things hidden.

"I'm not…"

"THERE YOU ARE, HUMAN!" Papyrus barged into the room with Sans tagging along behind him.

"Oh, good. Papyrus, would you help me to persuade-"

"I'm not registered." The words tumbled out of her mouth even before she could stop herself. Toriel stopped, looking through her reading glasses wearily.

"What do you mean?"

"…I'm not registered on the… government program thing. I'm nobody. I don't exist." Silence fell. Toriel regarded the girl with her scarlet eyes.

"I am concerned about how you were raised."

"It's a long story, but please. I can't be registered. I'll-"

I'll end up disappearing again anyway.

"…I can't ask you to trust me, but please. I'll do my best to study at home." Aria sent a pleading look towards Sans. Slightly shrugging, the round skeleton stepped forward, gently placing his phalanges on her shoulder.

"hey, what's the big deal? the kid seemed eager to learn when she was reading the textbooks. should be fine." Toriel shot him a stern look as he grinned cheekily. Sighing, she stood up slowly to murmur, "…I'll see what I can do," before leaving the room. Papyrus followed the goat monster, excitedly talking about a new spaghetti that he'll try cooking tonight.

"…so. you got nothin' to say, kid?"

"I'm not a kid, Sans. Stop calling me that." Aria sighed, exasperated. Sans grinned as he sat down on a chair slowly, his pinpoint pupils never leaving the young girl.

"then tell me your name." He noticed the visible flinch of the girl. Raising her eyes from the ivory desk to his eyes, she parted her lips slowly.

"…You don't remember, huh." The nonchalant expression of the girl felt out of place. It was as if she almost knew what was going to happen. Feeling coldness pool in a place where his stomach should be, Sans gulped.

"kid, i told you. i don't-"

"I'm sorry." The next word that tumbled out of the girl's mouth was what unhinged Sans. He closed his eyes.

"you know; I don't understand you. what's so hard about-"

"You won't be able to remember when I leave." The barely audible whisper of the girl hit him like a truck. What did she mean?

"kid, you need to tell me what's going on or i won't be able to trust you." Sans pressed on, ignoring the slight tremble of the girl. A bit more and…

"How about I show you?" The girl disappeared, electricity buzzing in the air. Sans whipped around to see the girl right behind him. She opened her mouth when-

-when he aimed straight for her throat, his eye burning cyan and yellow. Aria could've avoided him whenever, but she chose to stand where she was. Right before his phalanges enclosed on her pale neck, Sans stopped.

"…care to explain about that?"

"I… I choose to be experimented. By a monster."

"its name?"

"I cannot say. Names are very fragile thing… you should know that by experience. Chara."

"you-" The round skeleton's pupils widened as he summoned a gasterblaster out of nowhere. Aria only smiled. Extending her hand, she gently patted the nose of a monstrous weapon.

"Howdy." The gasterblaster nudged at her hand affectionately, earning a shocked intake of breath from Sans. Her melancholic smile seemed so far, so far away…

Sans eyes flashed dangerously as he jumped away from the girl, waving off the weaponised creatures.

"WHAT are you, pal?"

"Your greatest friend." Sans relaxed as he loosened his clenching phalanges. But she parted her lips again.

"Your worst enemy." He tensed again to summon magical bones and to pin her against the wall. His cold phalanges starting to curl around her neck this time, he growled.

"And that choice is not up to me, Sans." The girl breathed out quietly as her glass-like amethyst orbs glistened meeting his empty eyesockets.

"Please don't touch me. I don't want you to get hurt." She didn't struggle. Or put up a fight. She just stayed there, pinned against the wall with magical bones around her. Sans pulled back, sharply clicking his phalanges. The bones disappeared. However, the marks on the wall was clearly visible.

"…damn, toriel's gonna ask me-" Waving her hands in front of the damaged wall, electricity buzzed in the room again. The wall mended like magic, and his lifted his eyebrow at the petite girl for another explanation.

"…I can… repair things. That's one of my magic." Her eyes were shifting constantly. Sans lifted his eyebrow again, his baritone voice chilly.

"you suck at lying, kiddo."

"…I know." Aria grinned weakly. Sitting back down again, she motioned Sans the same. He sat down hesitantly, opening his mouth to ask,

"so, what were you doing with that bloody flower?"

"…mum couldn't have. She's strong. She's determined. She's-"

"…I'm sorry." The furry, humanoid monster pulled Aria into an embrace as she apologised. The girl stood still, recalling the events that had happened just few hours ago.

She was the first to be on the scene of dreadful sin. Her mum's office, splattered with still warm blood. Her mum lying in the pool of blood, almost cold, almost-

She told her not to cry. She also told her that she'll be able to see her again, well and healthy. She promised, right? And she never broke her promise, right?

…so much for a promise.

Aria demanded to see her mum. The monsters stopped her. She resisted. She was determined to see her mum.

And when she did, she was almost impassive. Almost.

Covered with a white cloth, she was so very still. Hands trembling slightly, Aria pulled the cloth that was covering her face.

It was beautiful. If anybody could look so peaceful before their death, it was only her mum. Dark circles around her closed eyes, long dark lashes, the still soft smile that was etched upon her face…

She couldn't be dead, right? She's only sleeping. They're trying to scare me.

Laughing hollowly, she reached for her mum's hand tentatively.

It was cold.

Her hands are usually cold, idiot. Feel her pulse!The voice in her head scolded her. Two thin, pale fingers touched the woman's neck where her pulse should be.

Nothing.

And then it hit her like a truck. She really was dead.

No more welcome smile when she gets home. No more spaghetti that she cooks. No more striped clothes that she should get for her.

"….Hah…" Aria exhaled shakily. She held her mum's hand and placed in on her cold cheek, kneeling down.

"Mum, c'mon, it's not funny. Wake up?"

Empty room.

Empty voice.

Empty heart.

She demanded again.

"Wake up! Please?" The girl rubbed the cold hand on her cheek, now pleading.

She's still alive.

I refuse to believe this.

"MUM. Please…" The tears that were held back broke freely as the pale girl continued to beg and plead for her mum to open her eyes. The silent sobbing crescendo-ed into a loud cry as she clung on to last hope, desperately trying to warm the cold hand with her hot tears.

"... Please, give my soul to Flowey when I… you know, in any case." Aria read out loud, her voice empty. The few monsters in the room gasped audibly.

"Flowey- but-" she didn't know what Flowey is. Mum never mentioned anything like that to her. But she knew that mum wouldn't do something stupid that will cause harm to any of her friends, or herself. Aria closed her eyes wearily.

"…If it's mum's will, then do whatever she says." Clarifying what she wants, Aria left the room. She desperately wanted her mum back. She was only fifteen.

"Howdy?" an uncertain voice echoed from outside. Aria, hugging her knees to chest, blinked slowly. The completely destroyed office was now free of bloodstains, but the sickly metallic scent remained the same.

"…um. Howdy?" Hesitantly standing up, Aria walked up to the door to open it. There stood a goat monster, still young. Short. Probably younger than her.

"…I don't want any visitors. Ple-"

"…Well, I'm Asriel, aka Flowey…" The voice trailed off timidly as he finished the sentence. Aria recalled the name Flowey and regarded him silently.

"…I guess the experiment was a success, then." The still impassive, still and hollow voice seemed to scare Asriel. Stammering quietly, he stared the ground, his goat eyes tearing up.

"I… I'm really sorry to hear about your mum. I knew her, you know-"

"And you got her soul. "

"I-"

"Get out." Her voice was too cold that it even scared herself. Asriel, stumbling, cried,

"Wait! Plea-"

"I don't want to see anyone. Please tell that to… your friends." Closing the door harshly, Aria leaned back on the door, sliding quietly. Curled into a ball again. The sound of thunder echoed from far distance. Slowly being enveloped by the darkness, Aria whispered,

"…Mum, what do I do?"

"kid. pal. kiddo. baby?" The baritone voice tinged with concern and playfulness took her by surprise.

"Gross, baby?"

"you were out daydreaming for about ten minutes. care to share?"

"No thanks."

"c'mon, caring is sharing."

"Pfft." Snickering, Aria met the white pinpoint pupils again. She exhaled slowly.

"I'm going to save Flowey. No, not just Flowey. I will save everyone."

A/N: And here's the third chapter! Thank you so much for the reviews! If I was to answer, SneaselXRiolu: your reviews are always interesting! I even incorporated some of your guesses to my fanfic (in my head it's going to work beautifully so yay!). Can't wait for more reviews from you :) ngrey651: personally, it does feel a bit clichéd, but there's a reason for why :D I won't let Aria to keep hiding so don't worry :)

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-HelloSkye-