Given the Undertale fics I've done lately, it's inevitable that I do a crossover of my own between Harry Potter and Undertale. But how to do it? There's a plethora of them involving Harry going through the same adventure as Frisk, with or without Frisk. There's a few other ones scattered here and there of different plots. But I eventually decided to do something very different. And it was sparked by a similar observation to one I had made prior to writing Verdant Magic. Undyne had red hair, and so too does Lily Potter. What if Lily was a Monster, somehow snatched from the Underground? What if she was Undyne's sister? And what would that mean for Harry?

People will see the DNA of both Verdant Magic and Haemophilia in this. This is also a story with an evil Dumbledore, so fair warning to those who don't like Dumbledore bashing. If enough people like this initial chapter of the story, and I'm able to write more before Christmas, it will be posted with the Christmas Update. Oh, and for those familiar with Undertale, there WILL be an explanation for Asriel and Chara's survival if you're confused. I do have some of it at the bottom of the page. For those who don't want any spoilers for Undertale, well, stop reading right here.

Incidentally, for anyone interested, I have two other Undertale fics: Dum Spiro Spero, a oneshot crossover with FEAR with Alma adopted by the Dreemurrs, and What Lies Beneath, a crossover with Final Fantasy X that begins in the Underground (with Yuna and Paine raised by the Dreemurrs) but soon goes out into Spira, changing things before the events of the game proper.

EDIT (December 6, 2016): Those paying attention to later contributions to The Cauldron will have noticed that I had, originally, opted to not go through with this story. I have since decided on another version of this story, with significantly less bashing, no Harry as a Monster (save by adoption), no Lily as Undyne's sister, and a very interesting pairing. It will still be set during The Goblet of Fire, Asriel and Chara will still be alive, and Harry, along with some others, will end up taken by the Goblet out of the Underground, destroying the Barrier in the process.

In any case, this version of the first chapter of Underground's Champion (which will be used for the next version of this story, as it's a good title and I enjoy confusing you lot anyway) will be marked as the original version. Keep an eye on The Cauldron for the first chapter of the new version. And give my other Undertale fics a go. Aside from the ones mentioned above, I have also posted a oneshot crossover with Death Note, called Queen of Spiders and Greatest Detective. And there will be the first six chapters, at least, of another crossover story, though you'll have to wait until the Christmas Update to see what it is.

UNDERGROUND'S CHAMPION (Original version)

CHAPTER 1:

KIDNAPPED

James Potter was restrained on the floor of his son's nursery, at the non-existent mercy of his enemy. An enemy who had admitted to dabbling in the foulest of magic. Tinkering with the soul ranked amongst the darkest of the dark magics. An enemy who had engineered betrayal of the worst kind against him.

He stared into the face of the enemy. The inhuman face, noseless, the slit-pupilled eyes glaring down at him balefully. In their monstrous hand, they toyed with a wand, tapping it against the palm of their other hand. And then, in an all too-familiar voice, they said, "What am I going to do with you, James Potter? I mean, you have been a thorn in my side for a very long time. Thanks to you and that old wether(1) Dumbledore, I have suffered humiliation, time and time again. That's no way for a Pureblood to behave."

James wanted to retort, but he couldn't, not with the Silencing Charm on him. He just glared defiantly at his enemy. It was all he could do.

"Then again, you'd do anything Dumbledore would ask you to do. You don't know that to him, you are a chess piece. Maybe not a pawn, but all chess pieces are, in the end, expendable, save for that of the king. I don't think Dumbledore cares about who or what he sacrifices, as long as he remains alive to be seen as the Leader of the Light." A scoff from his captor. "Using the moral high ground to mask his control of Magical Britain. Did you know he used to suck Grindlewald off? Well, near enough. He has the same obsession as Grindlewald did over the Greater Good, but he hides it, and he thinks the Greater Good is what he thinks of as good. The sad thing is, too many good people follow him. Hagrid, the Weasleys, the Longbottoms…good people, deluded and blinded by that old goat."

James wanted to snarl at his foe. Dumbledore had given him a wife and a child! He had promised so much, in exchange for helping him. How dare this vile thing demean that?

"You have hurt me and humiliated me for the last time, James Potter. And now, you're going to pay the price." With a wave of their wand, James was on his feet, staring into the eyes of his nemesis. His foe.

His wife.

No, not his wife. The thing that used to be his wife, even if she still had the red hair and the green eyes. His wife didn't have blue scales for skin, her eyes didn't have slit-pupils even while emerald, her hands didn't have webs between the fingers, which didn't have claws, and her mouth certainly wasn't full of shark-like teeth. A Monster.

The thing that was once Lily Potter, née Evans, glared into his eyes. "It wasn't enough that Dumbledore snatched me away from my family, my people. I had a happy life…but then, you and Dumbledore came along and used Amortentia on me. Even though conceiving while under the influence carries the risk of the child not knowing how to love. He wanted to create his own little weapon. My son. This prophecy has thrown a wrench into things, and that ritual he had me look into…he's hoping I would sacrifice myself to save my son. But I'm not going to, James. You are. I've already discussed this with Sirius and Remus. Oh yes, they know about the Amortentia. Sirius may be an idiot who doesn't really know about boundaries, but he knows you crossed the line. He's not happy with this…but he knows the truth, and so does Remus. Once Voldemort is dealt with, I'm heading back home, and taking my son, and your ex-friends with me."

James wanted to scream, to roar, to denounce his treacherous friends. But he couldn't move, he couldn't scream. Instead, he could only wait for the end. He caught a glimpse, out of the corner of his eye, of his son…except that blue-scaled thing couldn't be his son. No, that thing was just a Monster…

Hariacmon(2) 'Harry' Evans smiled to himself as he walked through Waterfall, back to his home, his family's home. He had just been visiting Sans and Papyrus in Snowdin. He knew his aunt got annoyed by Papyrus' overwhelming and loud enthusiasm, as well as Sans' bad puns, but the two skeletons were good guys. His aunt knew that, she just had a bit of a clash of personality with them.

Also, thanks to his aunt, he was something of a minor celebrity, if only because he was her family. She was head of the Royal Guard and at a young age to boot, seen as a prodigy. She was seen as the right hand of King Asgore, and, upon their reconciliation, Queen Toriel too.

Speak of the devil…there they were now, the royal family, barring Asgore himself, walking along the path. He knew they were coming to visit for dinner. Toriel Dreemurr, her biological son Asriel, and her adopted son Chara. A bit of a motley crew, to say the least. Especially as the latter two had, for a time, been dead.

Toriel and Asriel looked, for all the world, like humanoid goats. White fur covered the exposed parts of their bodies, they had long floppy ears and long snouts. Both had a pair of fangs poking out of their mouths, in a manner that managed to look endearing rather than sinister. Both had horns, though Toriel's were pretty short, and Asriel's were rather long. Toriel was dressed in a tabard embroidered with the Delta Rune, the sign of the Underground, and a depiction of a prophecy. Asriel was dressed rather more casually, in a green and yellow striped shirt and black trousers, as was Chara.

In terms of appearance, Chara was very different, though that was probably because he was a human. Or at least he had been once. He still had the outward look of a human, but there was something vaguely unearthly about him. Short brown hair framed androgynous features, and red eyes peered out from beneath his fringe. Both he and Asriel were now in their twenties, and acted as big brothers to Harry. Toriel was like a second mother.

Harry couldn't say they were odd, though. All monsters were odd, and he was no exception. He had the same blue scales as his mother and aunt, and the same green eyes as his mother, though he had the messy black hair of his…sperm donor. He had the lithe body of an athlete. A jagged, lightning bolt-shaped scar marred his forehead, though it was fading.

As usual, it was Asriel who noticed him first, and greeted him. "Howdy, Harry! We were just coming over."

"They wanted to," Chara corrected his adopted brother. "I just got dragged along for the ride."

"Don't be rude, Chara," Toriel chided.

"Or what, are you going to use those bad puns you've practised with Sans on me?" Chara asked with a roll of his eyes. "They may cause an allergic reaction in some people, but not me."

"Chara, Padfoot's with Alphys at his old home. They took Fawkes. They're hoping that they'll find something in the Black Library that will help destroy the Barrier," Harry said. "And Moony's off helping Mettaton with his new special."

Chara relaxed ever-so-slightly. Death and revival only worsened his misanthropy, specifically towards humans. Then again, over time, while he never truly let go of his hatred, it had lessened significantly. Exposure to Sirius and Remus helped, though he still felt ill at ease around them. Then again, he mostly tolerated the latter because he was a werewolf, almost a Monster by default.

Harry wasn't sure whether he was friends with Chara. The two got along well enough, despite Harry being only half-Monster. But Harry was more friends with Asriel than he was with Chara. And to be fair, Chara tended to keep to himself when he wasn't with his family. This was partly because of the attitude towards humans in the Underground, but mostly because of Chara's rather antisocial demeanour.

"It'd be Halloween on the surface tonight," Harry remarked. "That's what Mum told me."

Chara snorted. "Probably one of the few times that nobody would look askance at the Monsters. They'd probably think they were good costumes or something."

"It's practically a national holiday with the wizards and witches, all because Voldemort was vanquished," Harry said. He scowled. If it weren't for his mother recovering her true nature, he might have been orphaned, and kept unaware of his true heritage. He wasn't a fool: he knew that there were good humans, despite what Chara thought. But the thought of being kept ignorant of what he was…

They had come to their house, vaguely looking like an angry fish's head. As was her wont to do, even on a day off, his aunt was doing training exercises. "NGAAAAH!" she screamed as she sent a blizzard of magic spears at a training dummy, turning it into scattered rags and stuffing.

"Enthusiastic as always, Undyne?" Toriel asked.

Undyne turned to look at Toriel, and then smiled. Their relationship, when they first met, had been a bit rocky at first: by the time Undyne had joined the Royal Guard, Toriel had already exiled herself to the Ruins, over reasons that Undyne considered cowardly. It was Harry's mother who helped not only bridge the gap between the two and allow them to reconcile, but also begin repairing the relationship between the Dreemurrs. The fact that both Asriel and Chara were miraculously brought back from the dead helped.

While Toriel did prefer to stay in the Ruins, acting as a guardian of sorts, she travelled often, and while her relationship with Asgore was still distant, it was better than it had been, especially with the expeditions to the Black family home to find another way to destroy the Barrier. At least Asgore had, given Asriel and Chara's revival, been able to retract his declaration of war against humanity, even if he was still determined to break the Barrier. Hell, the only reason Sirius was allowed to live here was if he willed his soul to Asgore so that his soul could be used to break the Barrier.

"You know it, Toriel," Undyne said with a grin. It took her a while to stop calling Toriel Queen too. Undyne looked a lot like Harry's mother, with the red hair and all, though Undyne had a single golden eye, the other, due to injury, covered up by an eyepatch. She was also a bit more muscled. "Lily's inside, cooking up a storm. I'm jealous of how great she is at cooking."

"I brought along my butterscotch cinnamon pie," Toriel said. "I only wish Alphys was here. I had some of those snacks she enjoys."

Toriel's relationship with the Royal Scientist had also been strained, considering the experiments she had been involved in, including one that led to her son being revived as a soulless but still sentient flower. Only Alphys' regret and Asriel forgiving the reptilian scientist brought their relationship to an even keel, and Toriel took on a mothering role to Alphys.

They entered, including Undyne, to find the house permeated with delicious smells from the kitchen. His mother was just finishing bringing things to the table, and she smiled when she saw Toriel and her family. "Hey, Toriel, Asriel, Chara! Nice to have you all here!"

"It's good to be here, Lily," Toriel said. It took her a while to stop using her birth name, which was Lilethe(3), rather than Lily. That had been Dumbledore's contribution, upon seeing the name stitched into her blanket.

As they began to have their meal, Asriel said, "Didn't Uncle Sirius say that the Tri-Wizard Tournament's happening at Hogwarts?"

"Yeah, though I dunno why," Undyne said. "I looked at those books Lily and Sirius brought back. You know, know thy enemy and all that crap. They banned it years ago because it got too bloody dangerous. And yet, they're bringing it back. Sirius told me that one of the guys in charge was the guy who looked set to chuck him into Azkaban. Farty Crunch or something?"

"Barty Crouch Senior, Undyne," Lily corrected her older sister gently.

"Nah, my version's better. Sirius' all right for a human. Anyway, the other is some punch-drunk former Quidditch star. But to be honest, I think there's something wrong. I mean, after that riot at the Quidditch World Cup we heard of, with those former Death Eaters and the Dark Mark, well, something's going on. Just a gut feeling I have."

"We all have them," Lily said. "You, me, Padfoot, Moony…Voldemort is still out there. Especially given what we know about his Horcruxes."

Chara snorted. "So? Voldemort's not our problem."

"He's been defeated by Harry once, Chara, as I have told you before," Toriel said. "Someone like Voldemort cannot countenance such a thing. His ego won't allow it. If he ever finds out that Harry is in the Underground…and that's without going into the innocent lives he will destroy."

"Innocent," Chara scoffed quietly. He didn't say anything further, though he got up from the table.

However, shortly thereafter, Harry convulsed. He was sitting with Asriel and Undyne next to him, and as Chara passed, blue fire flared around the four of them. Suddenly, in a flare of azure light, they vanished, leaving Lily and Toriel to gape.

Shortly after that, Toriel's phone rang. She frowned when she saw the phone number, that of Mettaton, and answered it. In a distant voice, she said, "Mettaton, I'll need to call you back. Something bad has just happened." Lily watched as her friend's eyes widened in shock. "What do you mean, the Barrier just shattered?!"

In the Great Hall of Hogwarts, something big was happening. Not just the drawing of the three Champions from the schools of Hogwarts, Beauxbatons, and Durmstrang. No, this was about to overshadow that. They knew this when the Goblet of Fire spat out a fourth name, a name only two people in that hall had been expecting, even if they didn't show it. They showed shock and surprise, especially when the name on that slip of paper was read out by Professor Dumbledore.

"Harry Potter?"

The silence that followed was so thick, it could be cut with a knife. It was the calm before the storm. Harry Potter? The Boy Who Lived? The Boy Who Disappeared? Kidnapped by Sirius Black and Remus Lupin, foul traitors to the Potters?

Suddenly, there was a flare of blue flame near the Goblet of Fire. For a time, the azure flames flicked in a massive patch of fire on the stone floor, before finally, with a loud crack of noise like thunder, it dissipated, revealing a quartet of…people?

One of them was human enough, though the red eyes that peered out in anger from underneath a fringe of brown hair suggested otherwise. But there was a goat-like being, and a pair of fish-like people, one in his teens, the other apparently in her twenties.

It seemed that the Tri-Wizard Tournament had gotten even more complicated…

CHAPTER 1 ANNOTATIONS:

Hope you enjoyed this chapter, and yes, Chara and Asriel's resurrection will be discussed in detail soon. However, for those wanting details already, Chara's soul is his own (long story) while Asriel has the soul of James Potter. Originally, it was in Harry to protect him from Voldemort, but after finding Flowey and finding out who he was, they managed to transfer James Potter's soul into Flowey, allowing him to become Asriel again. We'll look at the details later.

What abilities does Harry have as a monster? You'll see, but he takes after his aunt as much as his mother. Lily's more able to use magic in general than Undyne, and has a specialty that links in to shifting souls. Harry has a similar ability to Undyne in that he can create weapons out of magic, though he creates swords in a not dissimilar manner to Virgil from Devil May Cry.

We'll also discuss how and why Lily became Lily Evans, and was married off to James Potter.

1. Wether, as mentioned in previous works I wrote, is a name for a castrated goat. I thought it a perfect insult for Dumbledore, even in works where I don't bash him.

2. Why Hariacmon? That sounds like a Digimon, but in fact, it's a variation of Haliacmon, the name of a Greek deity associated with a river. It's a bit of a stretch, but it fits in with Undyne's name…

3. Why Lilethe? Well, it sounds close to Lilith, and Lethe is both the name of a river that causes amnesia to those who drink from it, and the name of a deity of forgetfulness (which ties in neatly into Lily not knowing what she actually was for much of her life).