For Rias, defeating Raynare was never much of a challenge. After all, she was a high-class devil who wielded the Power of Destruction.
Even if Raynare was stronger than an average fallen angel of the lower ranks, to Rias, it still amounted to nothing more than a single blast of destruction.
And yet—even she couldn't do what Ren Kuroda had just done.
Crushing a spear of light with his bare hand, then instantly killing a fallen angel who had already fled several hundred meters away… that was on an entirely different level.
Just as she had observed Raynare earlier, Rias had also been watching Ren. But the aura surrounding him didn't belong to an angel… nor to a devil.
In fact, up until the moment he unleashed that bolt of lightning, Ren had felt like nothing more than an utterly ordinary human being.
"The power of fallen angels is weaker than I expected," Ren muttered to himself, glancing toward where Raynare had been. "I even tried to avoid any vital points… and she still died.
I was hoping to ask her a few things. Well, too late now. Not like she looked like the cooperative type anyway."
A casual comment—spoken as if he hadn't just obliterated an enemy hundreds of meters away in a single strike.
But what truly unsettled Rias wasn't the act itself—it was the fleeting aura he had released in that instant.
The sheer intensity of it made her heart skip.
That man in front of her… he might be human.
But he was definitely not a "normal" human by any stretch of the imagination.
The only time she had ever felt something comparable… was from her older brother—and her sister-in-law.
And her brother, Sirzechs Gremory… was none other than one of the newly appointed Four Great Satans—Lucifer himself.
When Ren's gaze shifted toward Rias and Akeno, both of them instinctively tensed, their bodies moving into guarded stances without hesitation.
But Ren merely gave them a brief, indifferent glance before turning away, as if they weren't worth his attention.
He then calmly walked over to the fallen Issei Hyoudou.
Looking down at the boy—his abdomen pierced clean through, his breathing faint and ragged—Ren reached into his coat and pulled out a small vial filled with crimson liquid.
"Well… since you helped me run into a fallen angel and a devil tonight—and you're technically my student—I'll save you this once."
The moment the healing potion from the YGGDRASIL system was poured over Issei's body, a soft green glow enveloped him.
Almost instantly, his wounds began to close.
The gaping hole in his abdomen shrank at a visible rate, flesh knitting together as if time itself had been reversed.
Watching this, Rias's eyes widened in shock as she stared at the vial in Ren's hand.
"…Is that… the Tears of the Phoenix?"
The Phenex clan—like the Gremory family—was one of the Seventy-Two Pillars of the Underworld, blessed with the traits of the immortal phoenix.
Their signature product, the "Tears of the Phoenix," was said to be the ultimate healing elixir—capable of instantly restoring any injury.
Though incredibly rare and expensive, it was precisely this miracle medicine that secured the Phenex family's extraordinary status in the Underworld.
Under the effect of the YGGDRASIL potion, Issei's body continued to recover.
But suddenly—
The Boosted Gear on his arm began to emit a blinding light.
Although his physical wounds were healing, Issei's body started trembling violently, as if enduring unbearable agony. Cracks began to spread across his skin, as though something inside him was tearing him apart.
"This won't work," Rias said urgently, stepping forward. "Even if the Tears of the Phoenix can heal his injuries, a normal human body simply can't withstand the power of a Sacred Gear awakening like this.
If this continues… his body will collapse!"
The unexpected turn caught Ren slightly off guard.
For a moment, he even wondered if YGGDRASIL potions had some kind of side effect in this world.
But Rias's explanation quickly gave him the answer.
"…His body can't handle the Sacred Gear's power?" Ren frowned slightly. "Then just remove it from him."
Rias froze for a second.
Then, seeing that Ren's expression was completely serious, a look of realization crossed her face.
So he's absurdly powerful… but completely clueless about basic common sense, huh?
"Sacred Gears can only reside within humans," Rias explained quickly. "If you remove it… the human serving as its vessel will die as well."
Since Ren had just used something as valuable as the Tears of the Phoenix, she assumed he genuinely didn't know this fundamental rule.
Ren clicked his tongue softly.
"…Then there's nothing I can do. Guess this kid's just unlucky.
In his current state, he probably wouldn't survive the infusion of a yokai core or even a spiritual power crystal either."
He shrugged lightly.
"We're just strangers passing by in each other's lives. I've already done what I could. At this point… all that's left is to hope he rests in peace."
With that, Ren made a clean, decisive choice—
He gave up.
And that, more than anything else, left Rias and Akeno completely stunned.
They had assumed Issei must be someone important to him—after all, Ren had just used something as outrageously valuable as the Tears of the Phoenix.
Even within the Phenex family, only a few vials were produced each year. Converted into human-world value, a single bottle could easily be worth dozens of Kuoh Academies.
And yet… after using something like that, he was just… walking away?
"I do have a way to save this student's life," Rias said after a brief pause, her tone steady. "If you don't mind… I'd like to make him one of my servants."
Truthfully, she had considered using a Devil Piece to reincarnate Issei from the very beginning.
But Ren's sudden appearance had forced her to hold back.
Now, however, she needed his consent—otherwise, provoking someone like him could lead to unnecessary conflict.
Ren waved his hand dismissively.
"If you can save him, go ahead. The kid's had a rough night—getting stabbed out of nowhere by a cute girl and all."
Years ago, the great war between the three factions had drastically reduced the numbers of angels, fallen angels, and devils alike.
In response, a genius from the devil faction developed something revolutionary—
The Evil Pieces.
A complete set modeled after Western chess, these pieces could only be possessed by high-class devils.
Each piece had a specific role, mirroring the abilities and values of their chess counterparts:
King – Greatly amplifies the owner's power, by dozens or even hundreds of times.
Queen – Possesses the abilities of all pieces except the King and Pawn; equivalent in value to nine Pawns.
Rook – Specializes in overwhelming attack and defense; can perform castling; worth five Pawns.
Knight – Grants exceptional speed; worth three Pawns.
Bishop – Enhances magical power; worth three Pawns.
Pawn – The most versatile; can promote into any piece except the King when conditions are met, and can freely change roles.
Each set consists of:
1 King
1 Queen
2 Bishops
2 Knights
2 Rooks
8 Pawns
A high-class devil can place an Evil Piece into another person's body, reincarnating them as a devil—and binding them as a member of their peerage.