Aura (400 + 31 years old)

"Aura. Thank you for saving the village chief and his daughter."

It was around the time the sun had completely set. In a remote, dimly lit corner room of an inn within a certain village, two figures stood.

One of them was a man named Himmel, standing in the center of the room. He was a hero by profession, aiming to defeat the Demon King, the ruler of the demon race.

"..."

The one he was speaking to had her back turned to him, busying her hands at a desk. She was a female demon, known as Aura, who worked as the merchant of the hero's party.

To Himmel, Aura was not only a demon—one of the very beings he was supposed to defeat—but also a mysterious figure who had always lingered at the edge of his vision since his childhood, ever since he first met Frieren. Even after joining forces with Frieren, who was driven by her quest to exterminate the demons, Aura was always at her side, so much so that Himmel initially thought it might be some strange gag.

Yet despite her demure appearance, she was a fearsome mage, capable of handling front-line combat with ease, her skills far surpassing young demons. Not only that, but she was extraordinarily competent at housework, child-rearing, and every miscellaneous task imaginable. As they traveled from village to town, she earned high income in short periods, covering their travel expenses. She was so monstrously capable that Himmel began to worry, 'If this continues, will I become completely useless as a human?'

"Aura, I bought it."

"You already have three things that do the same job…"

"No, this one is different! It's an amazing magic tool that cracks eggs automatically!"

As for her elf partner, who had practically become a freeloader by now, they had indeed become completely useless. Not only was Aura making a lot of money, but the demon's storage magic surpassed that of humans, giving her a large carrying space that was so large that she boasted she could fit a castle inside, and so Aura had become nothing more than a walking junk collector.

Setting that aside, Himmel had long since stopped questioning these oddities. Yet despite always being around Aura, this was the first time they were meeting without Frieren nearby, just the two of them.

Aura had recently cleaned up a mess caused by Himmel's misjudgment of a young demon, nearly preventing a tragedy. Now, Himmel had come alone to apologize.

"I only did what was necessary. If Zitrone had killed someone there, the criticism against me would have been strong, and in the worst case scenario, we would have been kicked out together."

"Hahaha... I suppose that's true."

Without turning around, Aura spoke the words that came out of her mouth, which were sound arguments based solely on calculation and risk management.

However, what this also revealed was that Aura, despite being a demon herself, trusted demons far less than anyone else in the village—perhaps even less than the hero's party.

"Zitrone...?"

"That's the child's name. Since I'm taking care of her, I'll be her adopted mother, so I gave her a new name."

"It means citrus lemon. Doesn't she seem like the type who'd just squeeze lemon on a big plate of fried chicken without asking?" Aura said something along those lines, which didn't entirely make sense. But the fact that she even understands jokes showed how intelligent she was as a demon.

"Is that all you came to say? Then you should get some rest. It'd be a disaster if the hero overworked himself and collapsed."

"Ah... you're right. Goodnight, Au—"

Flight Magic Even Humans Can Use

Coexistence Between Humans and Demons, Based on Ants and Aphids

A Magic to Cure Hangovers Quickly

Himmel's eyes inadvertently fell on the writing scattered across the desk as he was about to leave, and he held his breath.

Himmel had always considered Aura to be the typical cold, inhuman demon, someone who communicated only when necessary and lacked any real warmth.

"Aura, what is this...?"

"That? Just some research I'm working on. Though it hasn't been completed in over 400 years."

"Four hundred years... researching coexistence between humans and demons?"

"Well... yes, something like that."

The mere fact that Aura had even written the words "coexistence between humans and demons" was enough to completely upend Himmel's understanding of her.

Four hundred years—an unimaginable amount of time for a human, yet even for Aura, who had lived far beyond that, it could be considered a lifetime's research. And when he thought of it that way, her cold demeanor suddenly seemed like nothing more than a facade to Himmel. That was the curious nature of humans, after all.

"Do you truly believe that humans and demons can coexist?"

"Hm? Of course not. It's an impossible idea."

The moment Himmel tried to delve deeper, Aura's blunt response stopped him in his tracks.

"Wait, but this title—"

"Oh, right... I see how that could be misleading. But just because it's in the title doesn't mean that the research is about humans and demons being able to coexist."

After said that, Aura thought for a moment and said, "That's right," before speaking again. In the process, Aura tilted her own chair halfway and pulled another chair closer to the desk, motioning for Himmel to sit there.

"To put it simply, my research starts by acknowledging that humans and demons can never coexist. The real focus is on how they might be able to live in parallel, as a sort of compromise."

Himmel was surprised to see how politely Aura was treating him, though he also realized that her usual blunt demeanor had probably made him avoid talking to her in the first place.

"Coexistence and symbiosis...?"

"Yes, the two are similar but not the same. Coexistence is when two or more species of organisms simply survive and exist at the same time. Normally, humans and demons can't even manage that, so it's impossible from the start. Symbiosis, on the other hand, refers to two or more species living and surviving together while maintaining a mutual relationship. What I mean by symbiosis is specifically mutualism, where both sides benefit each other."

Aura further clarified, "Humans might call it 'supporting each other,' but it's simply a relationship where both sides avoid killing each other because they gain entirely different benefits from the relationship."

"The best example of mutualism would be ants and aphids. Aphids are just pests that attack crops, but they provide ants with honeydew, and in return, ants protect aphids from predators like ladybugs. This is the kind of relationship that forms in nature, even though the ants could easily just kill and eat the aphids if they wanted."

"I see."

"Applying this natural law to humans and demons, we aim to improve the kill-or-be-killed relationship. That's the ultimate goal of this research."

""Well, an ideal is an ideal, so the actual finished product will likely be far inferior," Aura muttered, then continued.

"As an example of how this might work... you've heard of orcas, right? Most of them don't attack humans."

"Is that true?"

"There are a few reasons for that. Some of these are just hypotheses, but for one, humans aren't chosen as prey by orcas because of their selective diet, like bears or demons. In short, humans taste bad, so orcas don't eat them. For instance, orcas only eat certain parts of sharks, like their livers. Since orcas are apex predators of the sea, they don't have much trouble finding food."

The topic had shifted suddenly, but Himmel decided to keep listening since it seemed important.

"Orcas are also known for retaliatory behavior. They seem to understand that if they attack humans, the humans will strike back, often excessively so. Out of fear of this, they avoid attacking. Additionally, it's said that the young orcas don't eat what their parents don't, so the behavior is passed down."

She continued, adding, "People also say that it's about love and affection, but I don't know anything about that and it doesn't matter."

"So, taking that into account, demons killing humans isn't just due to missing certain emotions. It's because demons have a selective diet that includes humans. On top of that, demons lack proper social structures and don't raise their young, so while they have the ability to manage risks, they don't pass down information about dangers across generations or peers. Demons also consider humans beneath them due to the vast differences in their magical systems. This is just a brief list, but you get the idea."

Aura added, "In terms of magic, demons don't pass on knowledge through child-rearing or mentorship, so whatever is learned dies with them in one generation, which is actually an advantage for humans."

"The biggest problem is that demons only possess individual knowledge about dangers, which is incredibly fatal. For humans, it's like not knowing that fire is hot or that water can drown you. Some individuals might not know until it's too late, and even then, they don't connect the dots. How could beings like that ever understand humans?"

She glanced at her bed, where a young demon child named Zitrone lay sleeping.

"That's why Zitrone thought of cannibalism, murder, and robbery as entirely separate things. She didn't even have the concept of atonement, so she acted as she did. The fault for this incident clearly lies with human ignorance. Who in their right mind would try to live in a cage with a tiger or bear that has tasted human flesh? Well, there were a few, at least."

"Haha... You didn't tell me earlier."

"You didn't ask, did you? You know that if you get carried away without being told to, some elf will send you flying into a wall and make you spit blood."

Apparently, the crisis management they just talked about also applies to Aura herself, and something happened in the past involving Frieren.

Though her tone was mocking, it was clear that if Himmel had asked first, Aura would have told him. Even though she was a demon, Himmel realized the importance of communication and thought he should talk to Aura more often.

"But Aura was considerate and helped the village chief, right?"

"... As I said before, it was because the disadvantages outweighed the benefits. Now, let's get back to the topic."

Cutting off Himmel's line of questioning, Aura continued her explanation.

"Demons do flee when they realize they're at a disadvantage, and they do fear death. It's not that they can't recognize danger, it's just that they lack the knowledge and don't share it. So, we can take advantage of that."

"Are you saying we can teach demons to recognize the dangers humans pose? And achieve symbiosis as well?"

"Exactly. That's why half of this research is like a manual on how to profit from humans, and the other half is a massive legal code full of common knowledge for humans. There's a lot more, but those are the two main points."

Aura sighed and added, "I feel like I could write an entire dictionary just teaching them not to kill humans," her lifeless eyes looking even more dead than usual as she muttered.

"In fact, the theory and method were completed after 400 years. Now I just want to run clinical trials and observe the results. If we can monitor demons coexisting with humans for about 500 years, I think we'll get decent research results. After adjusting the theory, I'll need about another 100 years."

"A thousand-year-long study..."

For humans, such a timeline was unfathomable, and even for demons, who are often killed by humans at a young age, it would be no easy task.

"For now, I'm testing what happens when a demon like me, who could easily slaughter large numbers of humans, raises that child as a mother and thoroughly teaches her both the dangers humans pose and the benefits they offer."

"I can even use the fact that she's tasted human flesh to our advantage. A normal demon would, anyway."

"Huh...? You'll become her mother?"

"...I'm a mother who gave birth to and raised three human children. Didn't I tell you before?"

"Eh...? Then that ring on your ring finger isn't just for show..."

"Isn't it natural for for married people to wear rings. I've been a widow for over 300 years."

She looked like a young girl, and considering how little she spoke—barely more than Eisen—it's no wonder Himmel had never known. But the more he talked to Aura, the more his preconceived notions about demons crumbled. Aura was an utterly strange and twisted demon.

"Is there anything I can do to help?"

"Hmm, let's see—"

After that, Himmel and Aura discussed how to handle Zitrone for a while.

As the night deepened, they ended their conversation, and as Himmel returned to his room, his steps seemed noticeably lighter.

After Himmel left the room, Aura gazed at the ceiling.

"I guess that's why that bastard let me live… It's damn annoying, but I had no choice but to serve him for 400 years until I died, and now that I've come this far on this ship, all my efforts up until now will be for nothing if I don't complete it."

She let out a long sigh, half-closing her eyes as she muttered to no one in particular.

"I know you're still watching, aren't you? At least... try looking me in the eye when you do."

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Next update is Aura & Frieren vs Omniscient Schlacht