The clouds drifted away and crystal moonlight spilled over the ritual circle. The edges were drowned in unicorn blood, a chaotic break to the coherent geometric symbols that Severus set up prior. Not for the last time, he wished he had delayed his arrival or found an opportunity to sneak away. After a summer of doing nothing, Voldemort finally decided to act.
And Severus was here, stuck, unable to warn the Order. The anti-apparition wards lay heavy across his skin.
He didn't even know what the Dark Lord intended to do tonight.
A somber silence swept over them as the Dark Lord stepped into the clearing. Rat bones cracked beneath his bare feet as he walked to the edge of the circle and waved his ivory wand. Nagini slithered up behind him, ready to strike. A few Death Eaters took a nervous step back.
"Pettigrew," hissed Voldemort. "The book."
Pettigrew rushed forward, a flaking book held in his silvery hand. His hair was plastered to his face as beads of sweat glistened in the moonlight. Trembling, he opened the book and bowed, passing it to the Dark Lord.
A rush of flame erupted through the air, and Severus shivered as the weight of dark magic slammed into him. He buckled beneath the pressure but forced himself to stand upright as others crumbled around him.
Ahead, the Dark Lord raised his wand, cut through moonlight, and began to chant. An unearthly echo of screams and agony greeted them. The unicorn blood rose in small droplets. One brushed against a Death Eater who had the misfortune to stand too close. He fell to the ground with a blood curdling scream. His body rippled and a wave of blood erupted, dragging more souls into its sacrifice.
The ritual, satisfied, coalesced in the center, beginning to take form.
Severus slammed his occlumency shields into place, finally giving him a moment to think. Dumbledore had asked him to keep his cover no matter the cost, unless Harry's life was in imminent danger. It wasn't, but he had to stop this madness regardless.
The air shivered around him, the fabric of the universe fracturing.
An explosion ripped through the clearing, throwing them to the ground. With it, the apparition wards shattered in a deafening bang.
Gritting his teeth, Severus stared at the dark cloud in the center of the circle. His magic buckled and writhed beneath his skin, tender and delicate, objecting to his demand. Whatever the Dark Lord had summoned, he could not be allowed to take command of it.
And with a crack, he was there, grabbing blindly. The Dark Lord's eyes widened. The betrayal registering. The world twisted away. A blind jump to somewhere. Anywhere, but here.
For the record, Lelouch would like to say he fully intended to accept his punishment in Hell with all the grace he could muster. But then, he found sweet, innocent Euphie in Hell, suffering for his mistakes. So he tried to plead her case to the gates of Heaven. It was an ongoing process—the bastards.
And of course, if Euphie—who had been so pure before he broke her—was in Hell, then his other angel of a sister would land here as well.
One thing led to another, until he found himself on the throne. It hadn't been entirely accidental, but he hadn't planned it either. Hell was better off for it, and he even enjoyed the job. He was good at organizing things and picking apart contracts. Best of all, his parents' eternal punishment was entirely in his hands.
Unfortunately, it came with one downside. Lelouch was quite sure that Satan had determined some solution for the issue, but he was, as his name suggested, Satan, and thus not very forthcoming. The bastard probably found the entire thing amusing. Regardless, Lelouch ultimately blamed Milly for having managed to summon him first... to give a speech of all things.
So in the midst of his meeting on making Hell more accessible with wheelchair ramps and auditory cues, he felt the annoying tingle. It always started at the back of his skull. Then the worst itch developed between his toes. Next thing he knew, he was falling through darkness and cursing the afterlife.
He woke to the taste of sand in his mouth, and a half dead man on top of him. Fruitlessly, he tried to push him off. When that didn't work, he glanced to the side where the sun slowly peeked over the treetops. Strangely, there were no entrails around, even if the man rather stank as if he were of Hell himself.
Bored, he poked at the man's soul. It was definitely going to be one of his subjects soon, but Lelouch wasn't one to judge. Heaven wouldn't accept Nunnally, which half tempted him to declare war to correct this egregious miscarriage of justice. Prudence won. Also, Heaven didn't have access to the internet, and Lelouch wasn't particularly keen on giving up that connection to his former life.
Finally, the man groaned. He pushed himself off him and patted his robes, which weren't tailored quite right. The material was also subpar. His brow furrowed, and he stared at Lelouch before suddenly grabbing a... stick?
"Ash wood isn't going to do anything. I checked," Lelouch informed him helpfully. He wiped the sand off his school uniform. It was always nice to have something familiar when embarking on unexpected interdimensional expeditions. "I'm rather glad you are alright, sir. It would have been very embarrassing to be found stuck under your corpse."
"Don't move." The man raised his stick.
"Look. Wood isn't magical. It does not ward off evil or whatever ridiculous notions you have. The worst you are going to do is poke me in the eye. Now, can we get to the next part? I do have somewhat of a schedule to keep."
A red light hit him in the face. Well, that was new.
Severus wasn't quite sure what he expected the Dark Lord to summon. An eldritch monster perhaps. But most definitely not a teenage boy. Still, knowing how deceptive appearances could be, he stunned him. Then, he apparated to Grimmauld Place.
"Severus?" Molly greeted "You were gone for so long, and so unexpectedly. We were worried that something might have— Is that a child!"
"Maybe." Severus dropped him into a nearby chair and took a step back, flicking his wand. Ropes and chains crawled up the chair, firmly securing the boy. He wouldn't be getting out of those. Strangely enough, he didn't have a wand or any other kind of weapon he could find.
"What is happening here?" Molly demanded.
"Yes. I would like to know that myself," Alastor grunts. His eye spins rapidly as he glances at the supposed teenager. "What is he?"
"The Dark Lord summoned him."
"And you brought him here!" Molly screeched.
"My cover is blown. My house is not safe anymore, and I have no idea what it is capable of."
Alastor waved his wand. "It's bathed in dark magic. Rennervate."
The creature gasped and jerked in the seat. It's eyes narrowed at them upon realizing it was chained. Then, to their surprise, it slammed its head backwards. "Why can't it ever be simple?"
Alastor stalked forward on his peg leg. "Who are you?"
"You summoned me. You tell me."
"We did not. We don't practice those kinds of Dark Arts," Molly said haughtily.
"You didn't summon me? Then... You interfered with the ritual?" For a moment it brightened, and an unsettling feeling washed over Severus, like the world was about to fracture once more. Then it settled, and Alastor had kicked over the chair, shouting, demanding to know what it had tried. The creature didn't even seem to notice. Instead, its unnatural, purple eyes focused on Severus. "Did you complete the ritual?"
"I interrupted it. We will determine how to dispose of you soon enough."
"But he's a child," Molly protested.
"It's not human," Alastor assured her, for once coming to Severus's defense. "We have no idea what it can do."
The creature raised an eyebrow. "While I'm all on board the sending me home train, there is a slight problem with your plan: I am already dead."
"Then how do we send you back?" Severus asked. The creature was strangely reasonable; it had to be a facade. The Dark Lord wouldn't go to such elaborate extents if it did not lead to death and destruction.
"Well," the creature began, his voice rife with teenage attitude. His students had better sense than to take that tone with him, but from a demon, the familiar tone sent shivers down his spine. "Normally, someone summons me. They complete the ritual, and tell me what they want. I do the thing if I'm feeling generous. Then they send me home. There's really no other way out of it."
"You are not returning to the Dark Lord's custody."
"Dark Lord?" the creature scoffed. "Who even calls himself that? I get Satan, but he invented the entire dark and gloomy bit."
"Satan?" Alastor echoed, and he finally stepped back. "Show your true self, demon!"
"This is my true self."
The spell hit the demon. His clothes rippled, growing longer, black turning to white stained red. A gaping, gushing wound grew on his chest, and the demon looked at them exasperatedly before taking a deep breath.
The wound faded. The clothes shrunk and darkened. The demon sighed. "Pardon me for not wanting to walk around like I just died. This form is close enough. I wore this uniform more than any other."
"But you're a demon." Alastor raised his wand. The entire nauseating process repeated again.
"Will you stop that? I do not wish to be here either. And yes, I am a demon, but I am still technically a damned human soul."
Molly staggers. "You died? At..."
"Eighteen." He shrugged and tapped his bindings. They fell away. "Anyway, if you could point me in the right direction that would be much appreciated. I was supposed to help with the amusement park later today. And then I have to blackmail some angels into attending the debate club, so they can finally get around to updating their three thousand year old justice system. Sending babies to Hell just to make our life worse is not fair. The daycare is overflowing."
"So you can help the Dark Lord take over England?" Alastor asked. "And kill all the muggles? We will stop you."
Strangely, the demon paused. "Muggles?"
"Non-magicals," Severus explained. "You don't know about magic."
"No, not your kind. Sticks are by far the least creative kind I've seen."
Alastor huffed. "They're wands."
"Sticks." The demon crossed his arms and leaned against the table. "A genocide then? Even a demon has standards. I was always quite fair to everyone. Well, then there is only one way to resolve this dilemma. You shall simply have to kill him, and I will be sent back to Hell."
Lelouch had thought these strange people—wizards, he learned—would be elated by his offer. It was a simple solution, and surely they were already invested in killing this Dark Lord—seriously, who called themselves that?—of theirs. Instead, he was hit by a red light and woke up again with his hands tied behind his back and the most obnoxiously dressed old man before him.
His wardrobe belonged in Hell... in the lava chambers where it could burn for eternity.
He was also, most definitely, insane.
"To clarify," Lelouch said slowly, "you want me to teach?"
"You want him to help me teach potions?" the dour man spat—and thank you! That was the appropriate level of disbelief for the situation. "That is an unknown dark creature with no knowledge of our magic, and you want to put it in a classroom filled with dunderheads who can barely refrain from blowing themselves up without demonic interference."
Lelouch leaned forward. "Is it like chemistry?"
"The demon knows chemistry. Of course the demon knows chemistry."
"Severus, my boy," the insane man began soothingly. Finally, a name! "We cannot risk the creature falling into the wrong hands, but you and I both know we cannot contain him. A man dies when the soul is disconnected from his body. That is why we cannot kill a ghost although they may be temporarily injured. That creature is a soul who made a body out of sheer force of will."
Had he? Lelouch closed his eyes, trying to remember the first moments of waking in Hell. He remembered realizing he was still aware. And then he opened his eyes. The new souls had bodies too, didn't they?
"The risk is too great. Lock it up in the dungeons until we finally kill the Dark Lord."
The old man sighed. "The risk is too great. We have no idea what he is capable of. You're quite capable of freeing yourself, aren't you?"
Pulling at the slight thrum beneath his skin, he nodded, and the chains fell to the floor. "I figured you would be more comfortable with the illusion."
"As you can see, Severus, our best chance is to entice him to stay here and make sure Voldemort's followers cannot reach him."
Lelouch snorted. Voldemort?
"Does death amuse you?" Severus snapped.
"Your Dark Lord failing French? Yes."
The edges of the old man's mouth quirked, and he pulled out a bowl. "Lemon drop?"
Warily, Lelouch accepted, surprised to find the delicate candy melting over his tongue. "Surely it isn't that difficult for you to kill one man. You are welcome to use me as bait and then drop a building onto both of us. It should solve your problem nicely, and I can finally return home without dealing with this ridiculous charade."
"I am afraid that is much too risky. What if Voldemort"—Lelouch stifled his snort—"has a way to bind you? Besides, if it only took a building, he would have long since perished and not risen from the dead."
"I was overdue for a vacation anyway," Lelouch grumbled, mind racing at the implication that a soul escaped from hell. He didn't count. As far as he knew, this was a problem limited only to him and had to do with his (accidental!) takeover of Hell. Unfortunately, the old man had a point. In the infinite multiverse, there very well could be a way to enslave him to the will of a mad man.
"Excellent!" The old man extended a hand. "Albus Dumbledore, Headmaster of Hogwarts. And may I ask for your name?"
Lelouch sighed, fishing through his pocket, and passed over his student ID. "I was Lelouch Lamperouge."
Dumbledore removed his glasses and wiped them before examining the card. "It says here you are the Vice President of Ashford Academy?"
"Quite the model student," Severus snarked. "You went straight from your graduation to Hell."
"Actually, I never did graduate."
"What did you do?" Severus demanded—a question which honestly should've been asked much earlier. Lelouch was beginning to be rather worried for the general safety of the students at school.
"In my defense, apparently my entire family for the last thousand years or so has landed in Hell. We may be cursed. For myself, I imagine the patricide had something to do with it. The bastard deserved it."
While Dumbledore turned grave, Severus merely nodded, a glimmer of understanding in his eyes before it quickly vanished.
"May I have your word that you will not harm the students?"
Lelouch smiled. "You do not have to worry. I have no interest in harming them."
"Well then, Taffie!" Dumbledore didn't even flinch as a warped creature landed on the table. "Please take our guest to the teacher quarters in the dungeons. He will be assisting Professor Snape."
As the door shut and the demon's sickly presence vanished, Severus relaxed in his chair. "Why my class?"
"He will have to sorted," Albus explained. "It's easier for a Slytherin to teach under their Head of House. Also, if anyone can manage him, it would be you."
Severus nodded solemnly. "The demon is dangerous. He killed his father at, what, eighteen? His true form also had a rather grisly wound. While alive, he was clearly accustomed to violence. And now he is a demon with unknown power at his fingertips."
"Yes..." Albus closed his eyes, and Fawkes flamed into the room. It crooned anxiously before huddling next to him. Stroking his phoenix's back, Albus continued, "He is a demon, and while it may seem unusual, he is bound by their rules. He cannot lie, only mislead and torture us with twisted truths. And if we extract a promise from him, he will be forced to keep it."
"And if he cannot?" Severus asked.
"Well, then he will no longer be a problem. A much simpler solution, is it not?"
Credit to OceanicEternity for writing the "Lelouch took over hell for Nunnally" fic which heavily inspired this. Credit to the discord server for spawning this purely self-indulgent fic by arguing over what Hogwarts House a post-requiem Lelouch would go into. Also credit to them for convincing me to post this because otherwise, it would've joined the graveyard of random writing scraps.