The first floor of the manor, in the guest parlor.
Leo and his group of four entered the luxurious room and took their seats.
The parlor was furnished with an ornate tea table and plush sofas. Every detail of the interior design radiated wealth—the furniture alone was worth a fortune, and even the carpet beneath their feet was clearly expensive. Hosting guests here left no room for embarrassment.
Yet Leo and Sona didn't sit inside. Instead, they moved to the open-air balcony beside the room. There, they sat across from each other at a small white table, the distance between them feeling far less formal.
Shinra Tsubaki stood behind a tea cart, taking the place of a familiar as she carefully prepared tea for them both.
Yukino stood quietly behind Leo, saying nothing, her posture calm and disciplined—she looked every bit the devoted servant.
With Tsubaki attending them, Leo and Sona chatted casually, like old friends catching up, while continuing their earlier discussion.
"So you're saying… your Evil Pieces choose their own reincarnation targets?" Sona asked, raising an eyebrow as she took a sip of tea.
"Exactly." Leo toyed with one of his Evil Pieces in his hand, rolling it between his fingers. "The first time I met Yukino, the piece reacted in a strange way."
At hearing Leo use her given name so casually, Yukino stiffened slightly, visibly uncomfortable. But Leo didn't seem to notice—or care.
"They seem to resonate with whoever they're most compatible with. When I approached Yukino, the Bishop piece in my hand began to glow."
That was something no other devil's pieces had ever done.
"While all of the pieces reacted to her to some degree, the Bishop piece's response was far stronger. So I believe the first change that happened when my Evil Pieces connected to my trait was this—it gives me hints, guiding me toward those most suited to become my servants, and even which piece fits them best."
Leo brought the piece closer to Sona, and it immediately began to emit a red light.
"See? It's reacting to you right now. It thinks you'd make a perfect match as one of my servants." He smirked playfully. "What do you think? Interested?"
"I wouldn't mind," Sona replied without missing a beat. "As long as you can convince the Sitri House—and my sister—I might consider it."
"Yeah, no thanks," Leo said, quickly pulling the piece back in mock surrender. "I could probably handle the Sitri House, but your sister? I have no desire to get on the radar of that siscon Maou."
He wasn't joking. The current Leviathan—Sona's sister—was one of the most powerful devils in the Underworld, her strength surpassing even standard Maou-Class. Some called her super-Maou-Class. Leo had no illusions about surviving her "attention."
"So that's why you gave Yukino the Bishop piece?" Sona continued, unfazed.
"I did consider giving her the Queen piece at first," Leo admitted, glancing back at the quiet Yukino behind him. "After all, she's a Longinus possessor. She certainly has the qualifications, and she deserves that kind of position. But after thinking it through, I decided to follow the piece's own choice."
In truth, Yukino really was best suited for the Bishop role. Her aptitude for demonic power after reincarnation made that much clear.
Her Sacred Gear wasn't a close-combat type—it was designed for large-scale, long-range destruction. That made her compatibility with the Rook and Knight pieces poor, something also reflected in the Evil Pieces' reactions.
When Leo first met her, all fifteen of his pieces had shown some response, but the Bishop piece shone the brightest. The Rook, Knight, and Pawn pieces had only faint reactions, and the Queen piece the weakest of all. It was obvious—Queen wasn't a good fit for her.
"That's the first change," Leo continued. "My Evil Pieces react differently to potential candidates. The stronger the reaction, the more suited the target is for that type of reincarnation."
It wasn't a hard conclusion to reach.
"And the second change?" Sona pressed. "If there's a first, there must be another, right?"
Leo snapped his fingers and smiled. "Exactly. The second change was just a theory at first, but after Yukino successfully reincarnated with a single Bishop piece, that theory turned out to be almost certainly true."
Yukino and Tsubaki exchanged confused glances, but Sona immediately understood.
"You mean… a Mutation Piece?"
A spark flashed behind her glasses.
"As expected of you," Leo said, grinning. "You caught on immediately."
"What's a Mutation Piece?" Yukino asked hesitantly. She knew it wasn't the best time to reveal her ignorance, but her curiosity got the better of her.
The one who answered her wasn't Leo or Sona—but Tsubaki.
"A Mutation Piece is a special kind of Evil Piece—an abnormal phenomenon that appeared when the Evil Piece system was first established," Tsubaki explained calmly. "It occurs randomly during the creation of Evil Pieces. Roughly one in every ten High-Class Devils is born with a single Mutation Piece. Normally, if a human's power and potential are too high, they'd require multiple pieces to reincarnate. But if a Mutation Piece is used, just one is enough to complete the Servant Conversion."
As Tsubaki spoke, understanding dawned on Yukino's face.
It was said that reincarnating a human into a devil didn't always require just one piece—the number depended on their strength and potential. For particularly gifted individuals, multiple pieces of the same type might be consumed for a successful conversion.
For example, the future Red Dragon Emperor had required eight Pawn pieces to reincarnate—an amount worth far more than even a Bishop or Knight (each worth three Pawns), and more than a Rook (worth five Pawns). Only the Queen piece, worth nine Pawns, surpassed it.
"Since Yukino is a Longinus possessor, it wouldn't have been surprising if she'd needed both of my Bishop pieces to reincarnate," Leo said. "But I only used one. And when I received my Evil Pieces, Beelzebub himself confirmed that I didn't possess a Mutation Piece."
He looked at Sona with calm confidence.
"That gives me reason to believe that my trait altered all my Evil Pieces—granting them the same properties as Mutation Pieces. In other words, I can reincarnate high-potential individuals with just one piece."
That was an extraordinary advantage.
For High-Class Devils, this was a common dilemma: should they focus on quantity—filling all fifteen servant slots—or quality, using multiple pieces to recruit powerful subordinates?
For Leo, that problem was even more significant, since his Servant Conversion trait granted him power feedback based on both the number and the quality of his servants.
But now? That worry was gone.
If all his Evil Pieces carried Mutation properties, he could focus entirely on quality—recruiting the strongest and most talented servants possible without losing any efficiency.
"That's quite an incredible development," Sona said, sounding genuinely impressed. "Fifteen Mutation Pieces... That's unheard of. I can't even imagine what kind of advantage this gives you."
"So far, it's all positive," Leo said, his tone measured and calm. "But whether there are drawbacks... I'll have to find out through experience. For now, I've only confirmed these two changes. If there are others, I don't know them yet."
"I'll report this to Beelzebub-sama," Sona said seriously. "He'll definitely want to review it himself. Now—those are the changes in your pieces. What about you?"
She leaned forward slightly, her sharp gaze seeming to pierce right through him. "You said your trait activates after you successfully recruit a servant, granting you feedback. Have you received that feedback yet?"
Under her intense gaze, Leo smiled faintly.
A sharp whoosh filled the air.
Three pairs of devil wings unfurled from his back, and an overwhelming surge of demonic power erupted from him like a blaze.
"This is—?!"
Sona's eyes widened.
"Six wings?!" Tsubaki exclaimed, stunned. "And that power...!"
It was stronger than her own master's.
How was that possible?
She distinctly remembered—Leo had only recently been promoted to High-Class Devil. Back then, his demonic power had been noticeably below Sona's.
And yet now, not only had his power surpassed hers, even his rank as a devil seemed to have risen.
"This is the result of my feedback," Leo said, retracting his wings and smiling. "Not bad, huh?"
As for Zenith Tempest, he didn't mention it.
Not because he didn't trust them, but because it was simply too soon.
A Longinus ranked second among all Sacred Gears—if word got out that he possessed such a weapon, it would shake the entire Underworld.
For now, Leo wasn't ready to wield it to its full potential. Better to keep it hidden until the time was right.