Hello readers! This is the first chapter of a little crossover story I decided to write between League of Legends and Undertale. I mainly started writing this because writing something different allows me to come up with better ideas for my main story (you should check that out too by the way). I always like writing something new so with this story I'm also now taking commissions, so feel free to put forward any crazy idea or pairing you'd like to see a story about via my PM (I usually reply pretty quickly). Anyway, I hope you like this story and feel free to leave a review if you feel like it.

Standard start of story disclaimer: I obviously don't own the rights to League of Legends or Undertale, and the story merely portrays my interpretation of the characters and worlds from these games.

Chapter 1 - The Ruins

"Hmm, a place like this is sure to hold all sorts of secret treasure! Perfect for attracting heroes!" I thought to myself as I overlooked the ruins of the ancient Demacian castle.

The castle had been in ruins long before even I had arrived in Demacia. Rumours from long ago surrounded the castle, claiming that it was a place of great magic. They told of valuable treasures sealed within the vault, guarded by powerful magic and dangerous monsters. Since then, many brave adventurers had attempted to explore the many underground passages, but all that entered were either met with disappointment or were never heard of again.

"Guess I'll set up camp while I wait for a hero to turn up."

Examining the surrounding area, I noticed one of the outer towers of the Castle looked relatively intact. The tower stood tall, seeming like a great place to keep watch over the surrounding area, while its sturdiness would provide excellent shelter against the harsh Winter winds that blew across the Demacian countryside. The steps were rugged and uneven as I climbed my way up them.

"How inconsiderate of these ancient builders not to cater to someone of my stature! At least carrying this hammer around keeps me in good shape."

Reaching the top of the tower I was relieved to see the roof was still intact, the old stone still holding firm against its millennial Winter. Rummaging through my backpack I pulled out what little I carried with me: a simple change of garments, several days worth of provisions, a tattered bedroll and a fairly sizable bundle of wood I had collected on my day's travels. After lighting a fire and laying out my bedroll the small tower room quickly became fairly cosy, far more luxurious than what I'm usually used to at least. After a quick dinner and with nothing else to do for the evening, I decided to call it a night.

"I've got to be up early after all, otherwise I might miss the hero!"

"Urggg… Come on, since when did Heroes take the Winter off!?"

I had been camping out in the old tower for almost two weeks now, and since then I hadn't seen any sign of anyone coming to explore the Ruins. Sure I had left occasionally to gather more firewood and to hunt for food, but I made sure to keep an eye out so I was certain I hadn't missed anyone. Looking outside I could see that a snowstorm was beginning to brew across the plains. "Well there's no way anyone is moving in this weather," I sighed. I was going pretty crazy from boredom after two weeks of almost nothingness, and seeing as there was no chance of any sort of hero turning up today, I might as well have a poke around the ruins.

"Who knows, maybe the hero of legend is trapped in some sort of holding spell down there? Awh, that would be so cool! They'll definitely like me if I free them from something like that, maybe I can even play a part in their great tales!" Filled with determination, I headed down the tower into the ruins below.

For a place that was almost 1000 years old, the castle corridors were still in great shape. The large stones that made up the walls were relatively undamaged, with only small cracks and a mossy residue covering the majority of them. The snowstorm outside blocked off any light that might usually illuminate the corridors, leaving the small torch in my hand as the only source of both light and warmth as I explored the ever expanding tunnels. At every turn I was greeted by another series of corridors and junctions, and before long I was deep into the catacombs of the castle, any semblance of sunlight long since gone. "Man, I can see why people get lost down here, I guess most of the people who don't come back simply can't find there way back to the surface" I mused, examining the occasional skeleton that I came across, "Maybe I should head back now..."

As I was considering heading back I came across a large room. An imposing statue of a great warrior stood in the centre of the room, standing ontop of a mountain of hideous looking monsters that lay vanquished at his feet. Surrounding the statue, rows of ancient scripture and historical carvings were embedded into walls. However, unlike how pristine the statue looked, the walls were stained and the text was faded away in some areas. Not that I could read any of it anyway, I was never much of a scholar but from what I could interpret from the carvings it looked like the room documented some sort of conflict between humans and monsters, ending in victory for the Humans. "Woah, Ezreal would have a field day down here, maybe I'll bring him back here in the Summer when some Heroes might actually show up."

Amazing as this room was I quickly remembered why I was here, and with a sigh turned my back on the statue and started to retrace my steps back to the surface. As I exited the room, I was stopped dead in my tracks by a low but powerful rumbling, shortly accompanied by violent tremors. "Damn! A cave in? Just my luck, the whole structure looked so stable too..." My anguish was quickly cut short as a piece of the ceiling stone narrowly missed me as it crashed to the floor. Holding tightly onto my hammer, I made a run for it.

The corridor wasn't that wide, but my speed and small stature made it much easier for me to dodge the falling rocks. However, my hopes were short lived as I turned the corner only to find a gaping chasm where the floor had once been. I searched around desperately, the only ways to go were either back down the corridor or down the chasm. Throwing my trusty buckler, I hoped to hear a clashing sound below, informing me it would be safe to jump. After a few seconds with no reply despair truly gripped me, my options had finally run out. With the corridor rapidly collapsing around me I decided a leap of faith had a much better survival chance than being crushed alive. Holding my breath I steadied myself, then I jumped.

"Urggggggggggggg…" I groaned as I slowly regained consciousness. My body felt like it was made of broken glass, but a quick check revealed that, despite the pain, nothing appeared to be broken. As I pulled myself up off the ground I found that the floor below me was not the cold stone slabs of the Castle above, but rather a thick bed of attractive looking yellow flowers. As I looked upwards all I could see was complete darkness, without any hint of the ruins above. I doubt these flowers, despite their softness, would've provided a sufficient protection against such a fall. "Maybe I crossed some sort of magic barrier that soften the fall? Guess luck really is on my side today."

Deciding to finally examine my surroundings I had a quick look around. The room was fairly large, but unlike the corridors above a soft ambient light brightened my surroundings. The floor seemed to be earthen, like a mine tunnel, but patches of flowers like the ones she had fallen into broke up the soft dark brown earth. I would be inclined to believe I was in some kind of natural cave system, but a large stone archway in the far corner of the room gave evidence to the contrary. Clearly someone had constructed this area. A faint glimmer caught my eye as I paced around the room, something small and metallic poked out of a flower bed. "Shieldy!" I exclaimed, as I rushed over to retrieve my trusty buckler, "I guess you're just as hardy as I am!"

As I reached to pull my shield from the flower bed a particularly large flower suddenly looked up at me, a goofy smile and bright eyes sat in the centre forming a face.

"Hey there! I'm Flowey, the flower!" The flower beamed up at me as I recoiled backwards in surprise, pulling my shield free from the ground in the process.

"Oh, hello there… Flowey..?" I replied hesitantly, not sure if this flower was actually talking to me or if that fall did far more damage than I had initially thought.

"Gosh you must be so confused, I guess you don't have many talking flowers up on the surface world do you? Don't worry I'll help you!"

"Oh, you'd actually be surprised," I stated, thinking about the huge variety of entities that fought in the Institute. "But then again... do you know where we are? I kinda need to get back to the surface."

"Why this is the Underground! Down here is home to all sorts of creatures just like me! Don't worry though, everyone down here is really friendly." The plant answered, still grinning happily at me.

"Oh… well that's good to hear I guess…" I responded. Secretly I was dreading the idea that this whole place would be full of weird talking flowers but listening to it seemed like my best bet at finding a way back to the surface.

"Oh I almost forgot! There's a tradition we have when greeting strangers down here! When meeting someone for the first time we show off our 'love' through little friendliness pellets!" As the flower finished saying this a small cloud of marble sized pellets bloomed forth. "Here let me share some with you!"

The small pellets started to hover towards me. Intrigued I looked carefully at them. They seemed harmless but I had a bad feeling about this whole situation, it seemed almost surreal and this plant was definitely being too friendly to someone he's just met. As the pellets drew close my instincts got the better of me and I ducked. No sooner than I did the pellets rapidly gained speed, crashing into the wall behind me.

"Hahahahaha!" A maniacal laugh resonated through the chamber, "Down here, IT'S KILL OR BE KILLED." A large burst of pellets flew out of the flower, covering the area behind it in a giant cloud of death. As the flower continued to laugh the pellets advanced rapidly towards me. I held my hammer and shield firmly in front of me.

"Well this is gonna hurt"

As I prepared for the worst, a wave of fire bellowed over my head, incinerating the pellets and blasting away the flower as it shrieked in pain. As I shielded myself from the heat a tall figure walked up beside me.

"Are you injured my child?" the figure asked in a soft voice.

I turned around to look up at my savior. To my surprise I saw yet another unusual character by my side. The figure was covered in short white hair, had long droopy ears and a pair of short horns stood on top of her head. Her appearance reminder me of Soraka, sharing some of the same animalistic qualities. From the long blue dress and the tone of voice it was clear that she was female, and her soft red tinted eyes had a look of concern and compassion in them.

"I'm fine thanks to you," I replied warily. "I mean, unless you're about to set me on fire as well. This whole place seems pretty dodgy if you ask me and I have no idea whether I should trust you any more than that flower."

"I'm sorry you had to witness that my child, and I understand your grief and confusion. The flower you encountered was a truly wicked creature that preys on those unfortunate enough to be stuck alone in these caves. My name is Toriel and I am the Guardian of these Ruins."

"Well nice to meet you Toriel, I'm Poppy and I'm…" I paused for a moment, trying best to describe myself. "Well I guess I'm just a wanderer with a big hammer." I finished, proping my hammer on it's end as I leaned against it. I tried my best to smile at her, but the look on her face turned to one of concern.

"Don't tell me a young child like you is a warrior?" She asked, staring at me intently.

"Oh wait no it's not like that!" I explained frantically, "You see this isn't actually my Hammer! I'm just sort of holding onto it for a Hero, you know I'm like delivering it to them! It's not like I go out fighting or anything."

"Though that kind of ends up happening regardless when I go to dangerous places were heroes hang out…"

Toriel's face once again softened as she smiled at me. "You poor thing, a young delivery girl that has fallen down then. I must apologise for my worry, not all people who fall down here are so friendly, many of them are vicious warriors that attack the residents of the Ruins. But fear not, I will protect you my child. Come this way, my house is not far away."

The woman turned to leave and beckoned me to follow. The woman's motherly tone was endearing, but she obviously had never met a yordle before and her treating me like a child was starting to get annoying. "Oh well, not like I have any better way to get out of here," I thought to myself, as I followed her through the stone arch at the far end of the cavern.

As I was led through a series of tunnels it became apparent that the so called ruins in the Underground were distinctively different from those of the ancient castle above. The stones were much brighter due to a certain degree of maintenance over the years, and the bricks that made up the wall were small and uniformly cut unlike the large slabs that made up the walls above. What also intrigued me were the number of traps and mechanisms that were still active. Toriel had unlocked several doors and navigated us through a multitude of pitfalls before we arrived at her house.

Like the surrounding ruins the abode was also very well maintained. And after being shown inside I was surprised by how modern the furnishing was. The floor was covered in rich wooden boards. The living room had many pieces of fine furniture, as did the bedrooms and other areas. The room that interested me the most was the kitchen, which was filled with technology that wasn't commonplace, even in Piltover. Electrical devices for both the heating of food for eating. cooling for storage and assorted devices I couldn't even recognise adorned the small room.

After a short tour and a cup of tea later, I was left to my own devices. Toriel told me she had some errands to run and that I should wait here for her to come back. She had given me a small device that would allow me to contact her if I needed too. I had never really used a phone before as I generally didn't visit Piltover much, but Tristana had been trying to get me to buy one for ages and in that time I had learnt how they work. I didn't really want to leave yet as I still had to ask Toriel for directions to the surface, but neither did I want to just sit around the house for her to return. Deciding that I could always call her if I needed too, I left the house to take a short walk around the surrounding ruins.

I soon discovered that there were indeed many strange creatures that called these ruins their home. These ranged from small talking frogs, shy wisps and even large talking vegetables. At first they seemed wary of me, but soon they continued about their usual without paying me much head. After around half an hour I came across an unusual sign covered in spider webs.

[Spider bake sale up ahead - all proceeds go to real spiders]

I shuddered slightly. Although I was usually not easily dissuaded, I really disliked spiders and my time on the Twisted Treeline had done little to help alleviate that fear.

"If the spiders down here are anything like the other monsters I definitely don't want to meet them" I thought to myself as I turned to retrace my steps. I was suddenly startled by a loud ringing sound coming from my shoulder bag.

"Eh? Is that the phone Toriel gave me?"

I rummaged around my bag before pulling out the small black box which was vibrating violently. Pressing the green button I held the phone up to my ear.

"Hello?" I asked hesitantly.

"Hello my child, this is Toriel," a crackly voice replied. "I hope you are not too bored there, there are plenty of books on the shelves you can help yourself too."

"Oh thanks, I'll keep that in mind but I'm OK at the moment." I replied guiltily, she would probably worry if she knew I left.

"That is a relief to hear, I just thought I'd let you know that I will be back soon, so just hold on for a short while."

Acknowledging this we exchanged goodbyes before I pressed the red phone button.

"I guess I better get back quickly, I should be able to get back if I follow this path…"

As I headed back down the way I came I was quickly stopped in my tracks by a strange ghostly aura emanating from the pile of leaves that had built up in the corridor.

"What on earth is this…"

I looked intently at the exoplasmic puddle that now occupied the floor. It was glowing dimly and emitting low humming noise. As I listened closer the noise got louder and I could hear it more clearly. It almost sounded like…

"Hey… are you… pretending to be asleep?" I asked, looking at the pool with puzzlement.

The sound quickly stopped and an uncomfortable silence filled the room. After a few seconds the pool began to raise off the floor shyly as it formed into a stereotypical ghostly entity. Now I had seen ghosts before but this one really did look like a bedsheet with eyes, if it wasn't for the very depressed look it had in it's eyes the sight would've almost been comical. The ghost slowly shuffled to the side of the corridor to let me pass, avoiding eye contact with me. I'm not sure quite why, maybe it was because I disturbed it or maybe it was how sad it looked, but I felt really bad for the poor ghost.

"Hey I didn't mean to be rude there, are you OK?" I asked, approaching the ghost.

"Oh no it's fine…" the ghost replied shyly. "It's just awkward because this place is usually empty, but I saw you were on your phone so I pretended to be asleep so you wouldn't notice me, but then I realised that I was in your way so me pretending to be asleep just made it even worse…" the ghost mumbled without pausing.

"Oh sorry I didn't know that this was any place special, I'm leaving anyway now so I won't disturb you anymore," I tried to give the ghost a reassuring smile. "I'm Poppy by the way, what's your name?"

The ghost looked up at me, apparently being reassured by my words. "Napstablook…" he replied.

"Oh well it was nice talking to you Napsta, but I've got to hurry off somewhere so have fun with uh… whatever ghosts like yourself do…" I gave one last smile as I turned to leave.

"It was nice to meet you too Poppy…" I heard him murmur slightly more cheerfully as I left.

As I looked over my shoulder to wave goodbye I saw that he had already disappeared. "I guess even ghosts come in all sorts of personalities," I thought to myself, picking up my walking pace. "I better hurry back before Toriel noticed I left."

I made it back to the house shortly before Toriel. After a nice meal that Toriel cooked for me we spent the evening casually talking to each other. I explained to her that I wasn't in fact a child, but a yordle in search of the Legendary Hero destined to wield the Hammer of Orlon. In return Toriel told her about her dreams of wanting to be a teacher and how she cared for many of the creatures in the Ruins. Eventually talk turned to the topic of leaving the Underground.

"Surely as the keeper of the Ruins you know how to get back to the surface? As nice as it is down here I can't stay forever." I asked Toriel.

"It is really no trouble, I have always wanted someone to share this house with and so you are very welcome here." She replied, smiling at me.

"No that's not what I meant…" I sighed, despite how kind she was Toriel had always avoided any questions I asked about leaving, and I was running out of ways to ask nicely. "I really need to get back to the surface, I have people I need to get back too! Not to mention this hammer isn't going to find it's own hero!"

Toriel looked away from me, a shadow crossing her face a she sat deep in thought. My feeling of frustration quickly turning to one of dread. "Could it be she doesn't know the way out?"

Toriel finally looked up and smiled at me again. "Maybe it's best if we discuss this in the morning. It's been a long day and you can't go anywhere right now."

I sighed in relief. I was still slightly worried, but she was right that I couldn't go anywhere this evening. Nodding my approval she led me to the guest room in the house. I had been awake since early this morning and it was hard to keep track of time in these ruins, but it certainly felt like it was late into the evening. Before long I quickly fell into a deep sleep.

A loud booming sound awoke me from my sleep. As I quickly got out of bed I heard another thud from deep below me. "What on earth is that? It sounds like someone is tunneling…"

As I dressed quickly and gathered my equipment I searched the house for Toriel. I had no idea what time it was, and a quick sweep revealed that my host was nowhere to be seen.

As I walked through the hallway I noticed that a door that had been previously locked now stood slightly ajar. When I had asked about it yesterday Toriel had said it led to the basement but now I wasn't so sure.

"THUD"

Another loud noise echoed from below. Deciding not to wait around I opened the door and crept down the dark staircase on the other side. After a fairly long walk down I arrived in another corridor, similar to those of the Ruins outside. Small candles flickered behind dusty glass giving an eerie glow to the musty hallway. Following the source of the noise I followed the corridor through several twists and turns. Fortunately there were no forks in the path and I soon arrived at the end.

Before me stood a huge door, probably around twice the height of a normal human, and many more times my own. The door, once ornately decorated was covered in numerous burns and the surrounding walls showed signs of cracks and other damage. In the centre stood Toriel with her back to me. She looked tired and it soon became apparent why as she shot a large burst of flames from her hands at the door, creating a loud thud, similar to the ones I had been hearing.

"Toriel what are you doing!?" I shouted at her in utter confusion.

She turned to me and through the obvious exhaustion on her face she smiled at me. "Poppy, you are already awake. I apologise, I hoped to be finished before then. Please wait upstairs, I'll be with you in a moment."

"No way! I'm not going anywhere! Is that the exit to the Ruins?" I asked angrily.

Her look turned to one of sadness. "It is yes, and I am about to destroy it, please don't stop me."

"Why on earth would you do that! I need to go home, you can't trap me down here!'

"Please understand, this is for your own good. All the humans that have fallen down here have left through this door have died"

I took a step backwards in shock, "They died? How!?"

"The King Asgore, he kills any human that comes down here and takes their souls to increase his power. I cannot let you leave here! I will not stay here and let you die!" She shouted, tears forming in her eyes.

Her words hit me like a truck. This place had seemed so friendly so far, other than the killer flower everyone had seemed so nice, was it all just an act? No I was naive in thinking that a place full of monsters would be some sort of underground Utopia. "Even if it was, I have to go anyway. The Hero would never give up in a situation like this!"

"Thank you for your concern Toriel, but I'm not the giving up kind!" I looked her straight in the eyes, "I'm gonna get out of here, and if I meet that soul snatching Asgore fellow on the way I'll show him some Demacian hammer diplomacy!"

Tears were streaming down Toriel's face. "Are you not afraid of death? It would be better for you to just stay here, at least here you can live happily!"

"I'm sorry Toriel, I'm a Demacian, and where I come from we complete our missions even in the face of death. I've been in some pretty rough spots before, but let me tell you I've never gotten out of them by hiding away!"

Toriel began to wipe away her tears. "I can feel your determination little one, it is greater than mine at the very least."

She smiled at me, before bending down and wrapping me in a tight embrace. "Please be careful, the monsters down here may resent humans, but they are good inside." Breaking the hug she turned around and using a key from her dress pocket she unlocked the door behind her.

"Don't worry, I'm a lot tougher than I look." We smiled at each other as I walked through the door. With a final farewell she closed it behind me, the lock clicking into place as I set out to escape the Underground.