Black Butler X Harry Potter Crossover

Pairings: Harry/Sebastian, Undertaker/OC,

Warning: Clichés, yaoi (Don't read if you don't like.)

Disclaimer: I do not own Black Butler or Harry Potter.

It has been several centuries since Harry collected the Deadly Hallows and became the Master of Death. Ever since becoming the Master of Death, Harry haven't aged at all. He remained at the age of 17, while his loved ones and the people around him steadily grew older.

It wasn't long before his friends became jealous of his youthfulness. Neville and Luna, bless them, weren't affected by that at all. Neville just smiled sadly at him when Harry told him about not aging. Luna waddled into the room soon after, carrying a tray of tea above her rounded stomach. She too, smiled sadly at Harry when he told her of his problems, a knowing glint in her eyes.

"Oh, Harry… Why is it always you?" She murmured as she caressed her stomach, leaning into Neville who placed the tray on the coffee table. The couple shot a look at each other and Neville nodded, clearing his throat to catch Harry's attention.

"Harry, we… we would like you to be our child's godfather. And for our future children, if we have any." He spoke.

"Me? Why me?" Harry set down his teacup gently, staring at his friends. "I mean, I am honoured and I would love to… but why me?" He questioned. He was not oblivious to the looks the couple kept sending him, but he was rather confused as to what it meant.

"Just because." Luna smiled mysteriously.

When he left, both of them hugged him tightly, and gave him some keepsakes. He got a radish charm from Luna, and a miniature sword with a tiny ruby gem charm from Neville.

It was some years after that that he realised why they gave those to him and made him the godfather of their children. Not long after his youngest and only daughter, Lily graduated, he discovered that Ginny was cheating on him. When confronted, she angrily admitted that she wanted a lover her age, and Harry looking the way he did made her feel old, which she disliked.

His 'best friends', the other part that made up the Golden Trio, drifted away from him when they realised he would remain young forever, essentially immortal. They were unhappy ( or jealous, Harry thought privately )that he would not be able to grow old with them and pass on together.

Harry didn't really realise what being immortal meant until the first of his children passed away, and he was the one to dig their graves. His friends had all long passed, and still he remained. Harry was devastated when he found out. No matter what way he tried, he couldn't die. At most he'll pass out for a week, and when he regained consciousness, he'll be good as new, body stitched back together as if he didn't just try to jump off a tall building.

To pass the time, Harry looked after the Wizarding world as a silent guardian. He paid special attention to the descendants of Luna and Neville, and his own family. He travelled all over the world, learning new information, but never, never interacting with someone more than he needed to. The deaths of his friends and loved ones still weighed heavily on his mind.

A century or so after the death of his friends, muggles found out about the Wizarding world. It was inevitable, seeing as how technology got more and more advanced as time passed. He was there when it started, and he was still there when it ended. Since then, many civilisations had rose and fell, and still he remained.

Harry stood alone in the middle of blackened and charred ground, fire burning merrily around him. Corpses laid around him, strewn in every direction and buildings lay crumbled and destroyed. The same sight met his eyes no matter where he looked. He sighed heavily to himself and looked up into the sky that was obstructed by black smoke.

"How many years has it been?..." He wondered, sighing again.

"More than 400 years, that's for sure." A melodious voice answered. The owner of the voice was standing beside him, eyes taking in the destruction of yet another civilisation.

"It wouldn't be long before another one rises again. And falls. It's a never-ending process." The person commented and Harry nodded silently, agreeing. He glanced at the person, mind going back to when he first met… her.

It was just after his first suicide. He had just buried the last of his children, and still filled with sorrow and desperation, he turned his wand on himself and firmly casted Avada Kedavra.

He awoke on the ground, at the exact spot where he killed himself. The first thing he noticed was a burning pain in his chest. The next thing he noticed was a stranger sitting serenely beside him. He winced and sat up, drawing the stranger's attention. Deciding to take care of the pain first, he pulled his shirt up and gaped at the tattoo he saw tattooed above his heart.

"Wha- What happened?! Why is that symbol tattooed on me?!" He panicked, before petite hands gently guided him to sit on the ground and a melodious voice cut through his thoughts.

"Calm down, Master. Everything is as it should be." Harry whipped his head up to stare at the stranger, mind processing and connecting the dots. He stood up again, with the help of the stranger and for a while, he just silently stood there, observing the stranger.

She was wearing a pitch black cloak with the hood pushed back. Long wavy raven locks tumbled over her shoulder, stopping three-quarters down her back. Green eyes, the same exact shade as his, stared back, with a ring of black surrounding the pupil, barely visible. The stranger was beautiful, in an ethereal way.

"You're Death, aren't you?" Harry spoke solemnly.

"Yes, Master." The being agreed.

It took sometime and a destroyed forest, for Harry to accept that he was the Master of Death. It also took some time for Death to stop being so formal to him, and the two agreed to pretend to be siblings if Harry was seen talking to her. Over the centuries, they grew closer and closer, treating each other as real siblings.

His skin eventually grew as pale as Death's, and his body became lithe and strong, a side effect of being the Master of Death, he supposed.

Harry sighed as he returned back to the present.

"It has been a long time, Death."

"Yes, it has. And I told you, my name is Lorelei!" Lorelei pouted. For an entity symbolising Death, she can be really childish, Harry thought fondly but sighed again upon catching sigh of the desolated wasteland.

"I am so tired of seeing this cycle repeat. There isn't even anyone left that I hold dear to, Luna's and Neville's descendants perished along with mine several centuries ago." Harry gestured to the land around them.

"That is true," Lorelei crouched and studied a corpse on the ground. "So you want something new, then?"

"Yeah, something like that, I guess." He ran his hands through his hand, messing it up.

Lorelei stood up abruptly and grinned at him, turning him to face her. "Okay, I got it! Let's go to a another world!"

"Wha- those exist?" Harry spluttered, bewildered.

"Of course they do! Hm… in this case, I think it's considered an alternate universe? That's what humans call it, right?" Lorelei scrunched her brow in thought.

"Explain."

""In this world, there are Shinigami - Death gods, Demons, Angels and of course, Humans. The Death gods are under me, and as you are my Master, you are the Head Shinigami, the Shinigami Lord." She explained, head tilting slightly before she added, "I guess you can call it my home?"

Harry gave her a deadpan look. "And you never told me about this because?..."

"You didn't ask me. And it's currently in the 18th century!" Lorelei grinned at him cheekily.

"Never mind that, just bring me there." Harry ordered exasperatedly.

Lorelei grabbed onto Harry and together, they faded in a black light.

So, how was it? I added some scenes and kept some of the original ones, but it was hard to make it flow smoothly so I'm sorry if it sounds weird in places. I also made the chapter longer, and I think one of the reasons the chapters I used to write were really short was because I paid a lot of attention to the word count. Please review and follow and favourite if you like the story!

Fun fact: Lorelei is associated with the legend of a beautiful maiden who threw herself into the Rhine in despair over a faithless lover and was transformed into a Siren who lured fishermen to their deaths.

Edited: 11 Nov. 18