Fate’s Slave - Shadow Slave X Honkai Star Rail

"Big bro, can you turn to the left a bit?"

"Uh… like this?"

A bead of sweat trickled down Sunny's face as he tried to get in a position that Griseo approved of. He wasn't sure why she had wanted to make a painting of him specifically, but he was somewhat glad that the younger girl had saved him from his predicament an hour earlier.

Or maybe it was actually a couple days? He had lost count of the amount of times the day restarted. This was actually the furthest he got.

***

As per usual, he went straight to training with his best pal Kevin after waking up. It was rigorous, but necessary if they wanted to defeat the Honkai. For Sunny however, it was absolutely deadly. He had been frozen, disemboweled, decapitated, and killed in a few other ways that Sunny couldn't quite describe.

Not that Sunny blamed him. To everyone else, he must seem like the strongest one around. It only made sense for Kevin to go all-out when fighting him.

It took a couple of tries, but he had managed to get through that hellish training without any real injuries. It was quite lucky actually, since he expected to have a couple wounds during the loop in which he actually survived. If that happened, Mobius would have probably dragged him to the infirmary, and Sunny didn't want to distract her from her research.

After consuming some delectable noodles alongside Kevin, he had run into Kalpas after roaming around Fire Moth HQ. Considering that everyone saw Sunny as the strongest, it made sense that a battle maniac such as Kalpas would want to fight him.

Sunny had long lost count of the amount of times he had been killed by Kalpas since he had met the man.

His checkpoint had been set to the start of the day, which meant he had to try and last against Kevin again whenever Kalpas killed him. After dozens of tries that usually ended with a hand sticking through his chest, Sunny had finally been able to return the favor.

…Of course, impaling Kalpas through the chest was not desirable. They were best friends after all!

After killing himself, Sunny had redone the loop with precision, repeating all of his movements perfectly. Once he was about to hit Kalpas with the finishing blow, he redirected his attack to only pierce his shoulder.

After a few minutes in the infirmary, his shoulder was completely restored. Kalpas had made him quite the meal — which usually happened whenever Sunny beat him in a fight. With a few parting slurs alongside a promise to kill him next time, Sunny bid Kalpas farewell.

Some people may find the man quite vulgar and violent, but Sunny simply thought of it as a way that he expressed himself. Even if it required him to die a few times, he didn't see any issue with letting Kalpas play around for a bit.

Planning to take a nap on the rooftop, Sunny controlled the shadows around him, manifesting two poles along with a hammock.

Unfortunately, he had been interrupted by a certain pink elf. Elysia came up to the roof mere moments after he had arrived, and stopped him from taking his nap. She talked about a bunch of random things, and had called herself cute way too many times. Normally, this wouldn't be too bad, but the door to the rooftop swung open, revealing Sunny's favorite scientist: Mobius!

…Actually, Mei was his favorite. Unfortunately, he had some bad experiences with saying such a thing in front of Kevin and Mobius.

He understood the former, at least to some degree. As for the latter… who knew what went through the woman's head?

Sunny didn't have any problem with being around Elysia or Mobius. In fact, he enjoyed it!

However, they always got much too hands-on with him whenever the other was around. Mobius was glaring daggers at Elysia as she asked for his help in the lab. Not that he was trying to brag, but Sunny was practically a scientist if one were to consider how familiar he was with the Fire Moth's lab.

Elysia had dragged him out of his shadow hammock, telling Mobius that the two of them already had business to deal with. Although that was obviously a lie, Sunny didn't say anything to refute it. The last time he had gotten stuck in the crossfire between them, he had pink arrows sticking out of his chest.

It was just an accident though! Elysia wouldn't kill him on purpose!

Thankfully, Griseo had rescued him when she asked him to model for a painting of hers. He immediately took the chance, running down the staircase with Griseo slung over his shoulder.

But… he didn't quite understand why Mobius was looking at him so smugly.

***

He had removed his shirt, which had been reduced to rags thanks to the many close calls he had with Kevin and Kalpas. There was a serpentine tattoo coiled around his body, and a circular, crimson symbol on his chest.

The serpent that seemed to be alive was reminiscent of the Honkai Beast that he had been merged with. It gave him the ability to both traverse and control shadows, which was quite useful for situations like these.

Unfortunately, it was quite weak. Whenever he went up against a Herrscher, he had to rely on his mind more than anything. He wasn't like Kevin, who could simply swing the Judgement of Shamash until one of them died.

It was usually Kevin.

Sunny suspected that the red mark on his chest had to do with his strange ability to return to the past whenever he died. He couldn't control when he returned to, so it tended to be quite inconvenient. Even worse, he wasn't able to tell anyone!

The strangest part was that the mark had been there his whole life. At least, as much of his life as he could remember.

He called the ability: 'Godslayer'.

He admits that the name is very cringy. However, it was the perfect ability for killing a godlike entity such as the Herrschers.

Anyways, Mobius had told him that the ability to wield Honkai energy was possible for any human with Honkai adaptability. The Honkai Beasts that the MANTISes had gained their abilities from simply awakened these abilities.

Supposedly, these abilities could be separated into six categories, but she wanted to run some more tests before she confirmed it.

Anyways, here Sunny was, shirtless while sitting on a stool as Griseo recreated his image. He thought it was a bit unusual for her to physically use someone as a model, since she could draw someone without them right in front of her.

Not that he was complaining. But Sunny was sure that there was something fishy going on.

"Just out of curiosity, why did you need a shirtless portrait of me?"

Griseo didn't stop painting as she answered him.

"Aunt Mobius wanted it. She said she'll get me new supplies if I do it."

Sunny nodded.

"Yeah, that makes… zero sense at all?"

Sunny created a portal into his small pocket dimension. After the death of the Second Herrscher, he had suddenly developed it's abilities — although to a much smaller scale.

He pulled out a premium painting set, complete with 72 colors! Tossing it over to Griseo, the younger girl caught it despite the fact that her eyes were still glued to her canvas.

"Hm… thanks. I already started though, so you'll have to wait."

Sunny sighed, but didn't complain about it. After around only five minutes, Griseo had finished her painting. Sunny didn't think that such a thing was normal.

"…You really did get my good side."

Sunny gave it a ten out of ten. A small smile appeared on Griseo's face.

"Don't tell Aunt Mobius what I told you."

Sunny grinned mischievously.

"Deal… also, Mobius isn't that old. Can't you call her big sis, or something?"

She was only a few years older than Sunny, who was twenty-three currently. Ever since he had first joined at the age of fourteen, six Herrschers had descended — and four of them had fallen. Void, Thunder, Wind, and Fire have been slain, Reason's still functioning brain was being picked by Mobius, and Death… was nowhere to be found.

Griseo shook her head.

"She's mommy's friend, so that means she's my Aunt."

Sunny sighed.

"Sure, let's go with that."

Griseo was often brought to Fire Moth HQ due to the nature of her parent's work. Her mother was a scientist that worked with Mobius, who Sunny also happened to spend quite a bit of time with. As such, they met each other, before becoming fast friends.

She stared at him for a second, before cutely tilting her head.

"Big bro, are you sad?"

Sunny was surprised by her question. He thought about it for a moment.

"No… I'm not sad. After all, only people that lose are sad."

Sunny smirked.

"Have I ever lost?"

Griseo didn't even hesitate before shaking her head.

Sunny chuckled.

"Well, there you have it. I never lose. And as long as I'm human, humanity will never lose against the Honkai."

…It wasn't the whole truth. Sunny knew about losing more than anyone. But in the end, he will win.

No matter what, the Honkai will be defeated.

***

In another era, a boy wearing a hospital gown roamed a small town in the Republic of Estonia. He knew nothing but his name: Sunless.

For some reason, he preferred to be called Sunny. Not that there was anyone to do so.

'Ah… it's cold.'

The town was devestated. Buildings were turned to rubble and corpses were littered on the streets — both humans and Honkai Beasts.

He had found himself in the midst of a snowy landscape, alone with only the hospital gown he was wearing as a possession. When he had found this town, everyone had already been killed by the rampaging Honkai Beasts.

He wasn't quite sure what happened, but his body had moved on it's own. Pikes that seemed to be made out of shadows strung up the monsters, putting them on display as they were relentlessly impaled by countless spikes.

Walking through the now-quiet streets with nothing but his thoughts, he wondered where those shadowy things had come from. They listened to him without hesitation, almost like he was a ruler, binding them to his authority.

Sunny also wondered if this place was where he was from. It was the closest town to where he had woken up, so maybe he had a past here.

He found that hard to believe. He wasn't all too interested in his past anyways.

Sunny paused when he heard the sound of… a child sobbing? He looked in that direction, reflexively dissolving into the shadows as he reappeared within the backyard of a ruined home. The sound seemed to be coming from above him.

Looking up at what seemed to be a child's treehouse, he once again experienced the strange sensation of traversing through the shadows.

Toys littered the floor as weak cries resounded against the walls. He walked over to a small toy box that seemed to have been slightly opened, probably to allow for air to get in.

Sunny opened up the box, watching in curiosity as the child hidden inside flinched.

She had short purple hair alongside matching purple eyes, seemingly younger than Sunny by a year or two. He wasn't sure how old he was, so his guess was based on his intuition.

Strangely enough, she was wearing pajamas that had a few buttons undone, exposing a strange symbol on her chest.

'How long has she been hiding in here?'

The girl made eye contact with Sunny, tears streaming down her face as she looked around the treehouse.

Meanwhile, Sunny's eyes were drawn to the red symbol on her chest. An unusual feeling welled up inside of him, as he looked down at his own chest under his hospital gown.

There was nothing on his body except for a single mark in the center of his chest.

It matched with her own.

Sunny sent a complex look at the girl for a second, before softly saying:

"What's your name?"

She averted her gaze. Her voice was raspy, hoarse from sobbing for hours.

"S—Seele."

Sunny tilted his head.

"No last name?"

Didn't people usually have those? Sunny didn't have one…

"Vol—Vollerei…"

Sunny nodded. Sending one last glance at the marking on her chest, he said:

"Okay. Then my name is Sunless Vollerei."

Her teary eyes looked up at him in confusion.

"W—what?"

Sunny gazed at her with determination.

"From now on, I'm your big brother, alright? You can call me big bro. Or Sunny. Either is fine."

***

In an era long gone, there had been thirteen heroes. In reality, there was actually fourteen.

The first Flame-Chaser: Deliverance/Treachery.

Freedom cannot be earned without betrayal.

And Rebirth cannot be without Death.