OKAY. So I know that I already have a 'Harry falls to the Underground' Fic that im working on, but im probably going to make more. Frankly, I love 'Harry Potter raised by other people' fanfics. And I'll make more- not strictly from Undertale mind you, but you get the point. ANYWAYS, this isn't a 'raised by' fic. This starts at the end of the Deathly Hallows. Harry is the MOD. And yeah, this is one of those 'Harry was Betrayed' fics. There overused- I get it. I can still love and use them, fight me. He falls during a Genocide route. Anyways, on with the Plotlines!

Also, I don't own Undertale, Harry Potter, or anything you recognize.

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Harry frowned, unfallen tears making his vision Hazy. Taking one last glance at the house behind him, he sighed and walked off. He officially had no-one to turn to now. Ron and Hermione left him, saying he was too dangerous, Dumbledore was dead, George was grieving the loss of his brother, Luna moved to France, and most everyone else was dead or didn't trust him. Neville was the one who suggested he move somewhere that bad memories didn't follow, he'd stay in touch. Hence why he was moving to America.

The plane trip was rather dull, the only other people in first class being Businessmen and this one blond dude with what seemed to be caterpillars for eyebrows. Actually- the plane ride wasn't so bad, he amended. The blond guy, Arthur Kirkland* was his name, was actually a rather good conversationalist. Apparently he worked for the government, and had a meeting in America. He was a rather nice fellow though.

Getting off the plane, he hailed a taxi and from there drove to his new home, a small cottage next to a mountain called MT Ebbot. Technically in the eyes of the government, he owned the mountain and thirty square miles around it. It was one of his father's old 'Vacation homes' so to speak. More like Vacation Castle, he thought to himself. And indeed, it was a castle.

Warm grey stoned made up the walls with cool blue roofing, and mahogany wood accents like doors and window shutters. Inside, the wood furnishings were mahogany, the floors being made out of birch. Blue and Purple accents were everywhere. Apparently before this was the Potter's estate, it belonged to a forgotten race. A long time back, it belonged to a race said to be locked away in the mountain.

And that had peaked Harry's interest.

Harry decided he would try exploring the cavern in the mountain, and if there was someone there? Whoopty-doo. He'd free them and give them back their land and castle, on the terms he could stay as well. If they wanted him to pay rent then? Sure thing, he had the money.

Picking out a room in one of the towers, he set his trunks and bags down, rolling his sleeves up his face set to a determined expression. "Time ta get to work." He said determinedly, deciding to clean his new room first and then work on the rest of the castle. Taking the white coverings off the furniture that protected them from dust, he admired the detail in them. Most if not all of it had intricate carving on them.

He came upon an indoor garden he decided to call the flower room, because of al the golden flowers that decided to grow here, some having vines that climbed up the walls. A few grew on the legs and back of a bench, with a pathway flowers didn't grow on leading to it and coming back around in a circle. On the sides, a few pillars stood tall, one had broken in half and the top lie next to it, flowers growing up and around the pillars. Yes, he'd leave this room be, it had a sense of calmness that he loved.

He found a room that had two grand chairs, so Harry assumed that this was the throne room. He went and polished the two magnificent chairs, but did not sit on them. He had respect you know.

Cleaning out a few more rooms, he found three small kitchens, and a huge kitchen somewhere else, and multiple bedrooms, storage rooms, and straight up empty rooms serving no purpose. He also found a few sitting rooms and a rather large living room. There were other rooms as well, but one caught Harry's interest. The library. IT WAS GIGANTIC! Now, Harry may have seemed like the type who didn't read much -not true- but in actuality, he absolutely loved books. And by the looks of it, these were the originals! The ones that had built this castle and ruled- these were their books!

Now done with his cleaning spree, Harry began to read, learning much about this race.

Apparently they were called 'Monsters' as a whole, with numerous sub-species ranging from adorable looking armless dinosaur-like monsters to frightening and powerful humanoid fish-like creatures. Harry was amazed, reading up on their culture, history, and an apparent war with the humans. There was no word what happened after the war though, nothing but a scribble saying 'They are going to trap us, a few have managed to escape but…' and the rest was unreadable. It was from a research book, the author's name nearly unreadable. All Harry got from it was W.D. -ST-R

Sighing, he put up another finished book, looking around for what he would read next. A pile of 'read' books slowly piling up. A faded once black coloured book caught his eye. From the style of writing -which he quickly deciphered- it was the same author, but he could se the other parts of his name. -.-. GA—E-

W.D. GASTER, if he put it all together. Humming, he read the title. 'Skeleton Magic Basic Beginnings' When he looked at where the book formerly resided, he saw a few sequels and picked them up, heading for a beanbag chair he had bought recently. Opening the cover to the first book, he began to read.

Apparently, if the author's research was correct, sense humans were 'descended from skeletons' a select few mages could perform skeleton magic. It was more of a side note than a real piece of text, thought.

Taking a bracelet off his wrist, he watched as it transformed into the elder wand. Staring at it, he thought. 'If I'm the Master of Death, theoretically speaking, I should be able to do this… or at least replicate it,' He mused to himself. Focusing on his magic, like the book instructed, he was able to summon two normal sized bones, but he was tired after it. Something was odd about the bones he created though.

They were black, with a white outline no matter the angle you look at them.

There was nothing about it in the book, the colours of magic it described were all vastly different. Trying a few different other types and colours of magic, he was surprised when they all looked exactly the same, Black with a white outline. Humming, Harry chalked it up to being an odd quirk of being the Master of Death.

At one point while reading Gaster's books, he found a rather sad and disturbing chapter. It told of how most monsters don't die unless something dust's them- a fancy term for murdering them. Either that, of their emotional state crumples to oblivion, though this only worked on emotionally changing monsters, such as a flame monster named 'Grillby' so says the book. Harry chuckled when he saw a heart or two right next to the name when it was mentioned. Apparently this 'Gaster' had a little crush on 'Grillby' he summed up.

Continuing his reading, it told how many fire monsters that were made of fire would die if they got too depressed, as their flames would get smaller when they were sad, and eventually put themselves out. There were other emotions as well, embarrassment and the flame would turn partially blue, anger and the flame would turn darker, and love would turn it pink.

Continuing, he blanched when he found a rather… odd chapter. 'Soul sharing' it was titled. Finishing that chapter, Harry was completely flushed red from head to toe. It was the monster version of the birds and the bees. Course, monsters didn't really have a biology, being made up of dust and magic, they relied on magic for offsping… Ahem. Enough of that.

Harry finished a few more of Gaster's books, and decided he would go explore the cavern atop of the mountain after he got skeleton magic down, which wasn't too hard to be honest. By around eleven o'clock at night, he had it down pretty well, also hearing the song that came when you battled with monsters. ((A/N: Think about the Lavender Town theme from Pokemon)) His was rather soothing… to him that is. If anyone else heard it, they would all agree it was one of the creepiest things they had ever heard. Apparently Death's taste of music was rubbing off on him…

Reading up on how to form a 'Gaster Blaster' he took notes dutifully, when he recognized something. He knew that skeletons talked in fonts, even were named after them, but he hadn't noticed he had been writing in one until now.

Libian SC Regular

Libian? Heh, it was readable to any other person at least.

Having a decent sized knowledge about monsters and Skeleton Magic/Monster Magic, he decided he would explore MT Ebbot the next morning. A morning that came too early in Harry's opinion. Sighing, he put on a green long sleeve shirt with black pants and a dark green almost black cloak with a hood. He grabbed a bag with food, water, and extra clothes and he set off to the mountain.

For what seemed forever he climbed, passing tree after tree, rock after rock, stopping only to admire a doe and a buck caring for their newborn. Finally making it to the peak, he saw the gaping hole and sighed. He couldn't die, so he might as well jump in. So what if he broke his neck? He'd come back as alive as ever, though his neck may be a bit sore for a bit. Humming his theme song, he jumped in swan dive style.

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Groaning, Harry sat up looking around. His neck, back, and arms were sore and he was surrounded by blood. He could guess what had transpired here. Standing up he, brushed off the fact he had just died and decided to explore. Finding a doorway, he entered the next room.

"Howdy! Im Flowey! Flowey the flower."

Ok, Harry hadn't expected that. "Harry." He said curtly, noticing almost immediately this creature didn't have a soul. "Say there Flowey, where's your soul? Death probably isn't too happy 'bout this…" The last sentence was said to himself but the flower monster still heard. "Death? What are you… You're different than the others… Its quite a pity that happened to the ex Queen you know… maybe you shouLD JOIN HER!" Flowey laughed, shooting a bullet through where Harry's heart would be, not bothering to start a formal battle. He watched gleefully as harry fell to the ground, waiting for his soul to be able to be taken.

…

It never popped out.

Instead, the human started coughing, blood dripping from his mouth. Wiping it away, the human, Harry, stood up again. "Wrong move flower. Unfortunatly, or I guess, fortunately, I CANT DIE" Harry hissed, menacingly, eyes glowing with black mist coming from his left eye, a few white wisps mixed in. Gulping, flowey fleed quickly, not looking back. Else, he would have seen a chuckling Harry. "Silly flower… like I would hurt him. Im not a Dursley." He said to himself, solving puzzles as he went through the ruins.

Thinking back on the flower, he remembered one part. "Its quite a pity that happened to the ex Queen you know…" And seeing all the dust around him, he was sure he wasn't the first to fall. And whoever came before him was bad news.

Coming across a small house, he searched it for any living thing. There was nothing. Signs show it hadn't been used in a while, and no one was to be found. When he found the diary though, he was surprised. It was… the Queen- uh, ex Queen… It was her home.

Checking the basement, his fears came true. A large pile of dust sat on the floor, next to a slightly opened door. Trimbling, he walked out. Down a long corridor. To a room, and then. Snow. Snow and cold.

Walking along the road, he stopped to investigate a stand that looked like a cross between a guard stand and a hot-dog stand. But there was no one there. There were two more stands. One had dog treats in a jar. Dust scattered in and around it. The other was normal, a broken sign on it. It had a layer of snow due to it being unused, but was otherwise fine. As he was inspecting it, though, a voice stopped him.

"Hey, what do you think your doing back here you Dirty Brother Killer, at his station no less…" It said,

Eyed widening, he turned to face the voice, a dark figure probably hidden with magic, and took his hood down, raising his arms in the universal 'I mean no harm' gesture. The figure noticeably faltered. "You… you're not… who are you…?" The monster asked, features becoming known. A short skeleton with a blue hoodie and a red scarf.

"Im Harry… Harry Potter… if I may ask, what happened? Why are they all… dusted…" Harry asked trailing off. "The little demon killed them… where did you come from anyways?" The skeleton inquired. "The surface, the castle still had all the old books, I read them, and decided I wanted to try and free everyone though… it seemed I was late…" Harry said guilty. "I can help though, stop it… if you want, I can try." He added. The skeleton nodded. "That would be nice, thank you… Sand, by the way. That's my name."

"Sans the Skeleton."