Yukino Yukinoshita left, taking the silently confused Asuna Yuuki with her.
Watching the two leave, Leon knew that Asuna Yuuki was probably still somewhat lost, unsure what to do next, which was why she hadn't particularly resisted his arrangement.
"It looks like I'll need to spend some effort guiding her."
Leon felt that leaving her alone might not be a good idea.
Although she could accept the current situation, Asuna Yuuki was fundamentally different from Yukino Yukinoshita. She might not be able to talk herself into quickly adapting to the devil identity like Yukino Yukinoshita had done initially.
Yukino Yukinoshita was aloof and unsociable, but she had always had clear goals. Her style of action leaned towards swift and decisive; she disliked dawdling or indecision. Therefore, even if left alone, she would push herself forward and required no deliberate prompting.
Asuna Yuuki was different. She had grown up under the strong control of her dominant mother, always living according to others' arrangements. Now, having abruptly broken away from her original life trajectory, if no one pushed her, she might become trapped in a self-imposed cage, struggling to escape.
Leon had checked not long ago: this world had neither fully networked virtual dive technology nor a quantum physicist and genius game designer named Akihiko Kayaba. Thus, Asuna Yuuki would not be locked into a death game and undergo a spiritual transformation there.
Without the threat of death, whether this girl would transform into the renowned Flash Asuna of his previous life was truly an unknown.
Leon silently noted this down, then activated his communication magic circle on his hand and contacted Sona Sitri.
"Good morning, Leo."
Sona Sitri's small projection quickly appeared on the magic circle, and her cool voice clearly rang out.
"Good morning, Sona." Leon held up the magic circle and smiled. "Did I interrupt you?"
"Of course not. It's the weekend, and it's not class time. You can contact me anytime." Sona Sitri returned a slight smile. "How did it go? Was the subjugation mission completed?"
"It's done." Leon shrugged. "But I have something I need your help with."
With that, Leon recounted the entire process of subjugating the Stray Devil from the previous night to Sona Sitri.
Sona Sitri wasn't surprised to hear that Leon had successfully dealt with the Stray Devil.
It was a mission she had passed to Leo, and she had information on that Stray Devil, knowing that it was only a Low-Class Devil before betraying its master, possessing at most the strength of a Mid-Class Devil now. It was no match for Leo.
Therefore, Sona Sitri wasn't worried that anything would happen to Leon on this mission.
However, she was surprised when Leon mentioned encountering a victim and reincarnating her as his servant.
"Blade Blacksmith?" Sona Sitri said with surprise. "The new servant you've taken on actually holds that kind of Sacred Gear?"
"Yes." Leon smiled faintly. "This counts as an unexpected surprise."
"It truly is an unexpected surprise. A Devil servant possessing a Sacred Gear capable of creating Holy Swords—the Church side would likely be quite helpless if they heard the news, wouldn't they?" Sona Sitri pushed up her glasses. "And Rias; she might have a reaction if she knew one of your servants holds this Sacred Gear."
"Oh?" Leon blinked. "How so?"
"She has a servant who is the same 'Knight' piece as your new one." Sona Sitri explained, "That servant is also a Sacred Gear holder, and the Sacred Gear he holds is the complete opposite of your servant's, a related Sacred Gear—'Sword Birth'."
"Sword Birth", as the name implies, is a Sacred Gear capable of creating Demonic Swords.
Demonic Swords are the complete opposite of Holy Swords—weapons filled with demonic nature and curses.
Like Holy Swords, Demonic Swords have also appeared in various legends.
Gram, Balmung, Nothung, Tyrfing, Dáinsleif... these famous weapons are all Demonic Swords. Each is incredibly powerful and possesses special abilities. They are not as selective about their users as Holy Swords; they don't require decades to find someone who can wield them. However, their users are afflicted by the swords' curses, and without a way to resist the curse, they will eventually lose their lives.
"Sword Birth" is the Sacred Gear used to create such weapons. It possesses a power that is the same type as "Holy Sword Creation" but completely opposite.
"Holy Sword Creation" is a Holy-attribute Sacred Gear, and "Sword Birth" is a Demonic-attribute Sacred Gear. While they wouldn't necessarily fight to the death every time they appear together, unlike the legendary Red Dragon Emperor and White Dragon Emperor, they can still be considered natural competitors due to their nature.
Especially Rias Gremory's "Knight"—if Leon remembered correctly, that person seemed to have an inextricable link with Holy Swords, viewing them as enemies and wanting to destroy them.
If he were to run into Asuna Yuuki, he might resent her through association?
"Then I must urge Asuna to quickly grow stronger so she won't be bullied by a fellow servant-devil."
Leon joked with Sona Sitri.
"It won't come to that. Rias will handle that kind of thing." Sona Sitri gave a slight laugh, then continued, "I understand why you came. You want to properly mentor your 'Knight,' so you need knowledge related to swordsmanship and sword techniques, right?"
"I can't help it. The Ellig family is old-fashioned; our family library basically has no knowledge of this kind, or perhaps it did, but it wasn't included in what was returned to me?" Leon said helplessly. "I can only ask you for help."
"That's a small matter. As long as you don't ask for the secrets passed down through the Shitori family, I can take the liberty of providing you with the relevant knowledge." Sona Sitri said, "However, are you sure just having the related knowledge is enough?"
"What else?" Leon paused slightly. "Do you have a better solution?"
"...Something like that." Sona Sitri hesitated for a moment, which was rare for her, and then sighed, saying, "If you need it, I can introduce you to a swordsmanship instructor."
This piqued Leo's interest.
What kind of swordsmanship instructor?
Sona Sitri knows someone like that?
Why did she react that way when bringing it up?
"To be deliberately brought up by you, this so-called swordsmanship instructor must be something special, right?"
Leon stroked his chin and asked.
Then, Sona Sitri dispelled all of Leo's doubts with a single sentence.
"That is my sister's 'Knight'."
Sona Sitri's casual statement instantly stunned Leo.
Sona Sitri's older sister... the current Devil King Leviathan?
A Devil King's servant? And a 'Knight,' just like Asuna Yuuki...?
Hiss...
"Is that... really okay?"
Leon felt a shameful urge to take the offer.
That was a Devil King's servant!
The servant of the current Devil King Leviathan would have to be an Ultimate-Class Devil at the very least, wouldn't they?
Was Sona Sitri being this generous? Directly finding an Ultimate-Class Devil to be a tutor for her servant?
"It should be fine." Sona Sitri said with a slight stiffness. "As long as I ask my sister, she shouldn't refuse."
Of course. She was a siscon Devil King; how could she refuse her adorable little sister's request?
It's just that Sona Sitri would likely be tormented by her sister for a while. She was the one who was most embarrassed and resistant to her sister's doting and spoiling.
Yet now, she was willing to make such a big sacrifice for her own servant... She truly was dedicated.
However...
"Your sister won't become hostile towards me just because you specifically asked her for my sake, will she?"
Leon became somewhat wary.
It was well-known that siscons were unreasonable beings. Once there was any possibility of their sister being led astray by an outside opposite-sex individual, these unreasonable beings would not hesitate to use any means to eliminate the threat.
Even if Sona Sitri only spoke up for him, requesting to borrow a servant as a tutor from her sister, the other party might irrationally resent him.
Leon was no stranger to this kind of hardship. When Sona Sitri first came to the Human World, became his supervisor, and they unexpectedly formed a good relationship, that person had secretly caused trouble for him.
Although the other party was later angrily scolded over and over by an utterly mortified Sona Sitri, who was so struck by shame she couldn't eat for three days, Leon still received sporadic news over the past three years, knowing that the person had been keeping a close eye on him.
If he ever made a move on her sister...
Leon couldn't help but shiver.
"Don't worry. Supporting you is part of my mission in the Human World. Especially after submitting your report last time, I was instructed by the higher-ups to satisfy your needs as much as possible to ensure your growth is unimpeded."
Sona Sitri offered Leon some reassurance but still sounded a little uncertain.
"My sister... she probably wouldn't openly violate the operational policy set by the higher-ups in the Underworld for such a trivial matter, would she?"
...Perhaps, but it would be more convincing if you could sound a bit more certain instead of so unsure.
Forget it. Consider it the necessary price to pay for the future of my servant.
It's just a Devil King, after all. Once I develop the Balance Breaker for 'Zenith Tempest', I might not be unable to take her on head-on.
"Then I'll leave it to you."
Leon handed the matter over to Sona Sitri, reaching a conclusion.
"No problem. Wait for my news."
Sona Sitri was also committing herself wholeheartedly. Although she wasn't keen on interacting with her embarrassing sister, for the sake of her friend... she'd do it!