"The first thing to clarify is the nature of Kidō attributes," Renya began, sitting across from Suì-Fēng in the training hall. "Wind can enhance speed, but not to the same extent as the lightning element. Moreover, when it comes to Hadō, lightning-based techniques are by far the most numerous. Captain Suì-Fēng, are you certain you want to base Shunkō solely on wind Kidō?"
He fixed his gaze on her, speaking with rare seriousness.
Suì-Fēng narrowed her eyes, answering firmly. "Thunder does provide explosive acceleration, but wind carries destructive persistence as well. That's why I chose it."
Renya shook his head. "But in terms of destructive output, wind doesn't necessarily surpass lightning—and it certainly can't rival fire. Consider this: the explosive shockwave you generate with Shunkō detonates on contact, destroying the target through sheer concussive force. But Yoruichi-sama's Raijin Senkei—her lightning-clad form—produces raw speed and destructive power far beyond that. Her thunder cannons alone can obliterate targets with divine force."
He paused, recalling past battles. "Even Shihōin Yūshirō's Shunkō manifests with fire, and his Shunkō: Baku'en Musō created a massive explosion—like a mushroom cloud. That destructive force eclipses most forms of elemental Shunkō."
Suì-Fēng folded her arms, voice sharp. "I don't require extreme destructive power. Persistence is my priority."
At her words, Renya's thoughts drifted to her Bankai: Jakuhō Raikōben, the Hornet's Thunder Whip. Though restricted by activation conditions, it was one of the most destructive weapons among the captains, capable of annihilating entire fortresses in a single strike. If she valued persistence, it was because her ultimate weapon was already devastating enough.
"And yet…" Renya pressed, "the sustained flow of wind might be reliable, but lightning offers speed—the kind of speed that amplifies your Zanpakutō's true strength."
Suì-Fēng tilted her head. "You're suggesting absolute speed is what I should pursue?"
Renya nodded. "Exactly. Think of it: your Shikai, Suzumebachi, is specialized for assassination. Two consecutive strikes on the same spot ensure death—the Nigeki Kessatsu. What better partner for that ability than unparalleled speed? If you refine lightning-based Shunkō, your assassination ability would reach its highest potential."
He chose his words carefully, avoiding a direct explanation of her Zanpakutō's abilities, but hoping to draw her acknowledgment.
Suì-Fēng finally admitted, "My Shikai is indeed Suzumebachi. Its ability requires precision. From that standpoint, speed would complement me best."
Renya's expression hardened with resolve. "Then my suggestion is this: adopt lightning-element Kidō as your base for Shunkō. Pursue the ultimate speed, and pair it with your Nigeki Kessatsu. That synergy would maximize your combat power."
Suì-Fēng fell silent, thinking. At last, she said, "You're not wrong. But shifting to lightning would invalidate years of my research. I'd be forced to start again from zero."
Renya shook his head. "Not completely. Didn't you already decide where to anchor the Kidō flow in your body?"
She nodded. "Yes. My initial plan was to channel the Kidō around my back and shoulders, infusing my limbs with explosive power."
"Then that's a perfect starting point," Renya replied. "The spine is the axis of movement. The back muscles provide stability, the shoulders power the arms, and the waist grants flexibility. Using the back and shoulders as conduits is a logical choice. But the real challenge lies in the conversion."
Suì-Fēng tilted her head slightly. "Conversion?"
"The transformation of Kidō," Renya explained. "Kidō is spiritual energy given form. Each spell manifests differently. Choosing the right thunder-type Kidō as the basis, and refining its nature, determines how effective your Shunkō becomes. We'll need to experiment, dissect the nature of each spell, and adapt them for this purpose."
Suì-Fēng's lips curved faintly. "That's precisely the problem. When I was working with wind-element Kidō, I tried several spells, but none meshed properly with Shunkō's flow."
"Then we'll search slowly," Renya said with a calm smile. "Study the distinct properties of thunder-based Kidō, then merge them. For example, Yoruichi-sama's lightning form resembles Byakurai in its piercing discharge, but its explosive qualities echo Hadō #63: Raikōhō. If we can understand and refine the essence of these spells, we can forge a stable thunder-based Shunkō."
Suì-Fēng crossed her arms again, thoughtful. "…Then I'll apply to the Kidō Corps for training. I'll learn every thunder-type Kidō available. Once I've mastered them, I'll share them with you. Together, we'll test which works best."
"Perfect," Renya said. "And beyond the Kidō itself, the release angles and energy flow matter just as much. Even if we anchor at the back and shoulders, changes in spinal alignment, back muscle contraction, or shoulder rotation will affect output. We need to map how energy transfers into each limb, and how to distribute it efficiently."
Suì-Fēng exhaled sharply. "That alone could take a decade. Maybe more."
Renya nodded gravely. "I know. In the original records, it took you nearly fifty years to develop Shunkō—and even then, it wasn't complete. The Mugenzan Shunkō you later devised was just an evolution of your original wind-based form, extending its flow from the back and shoulders to your entire body. Yoruichi-sama followed a similar path, but hers was always thunder. Neither of you ever shifted attributes—because the cost was too high."
She remained silent, her gaze unwavering.
Renya continued, "Different elements demand rebuilding from the ground up. Once you commit to an attribute, changing it means re-learning everything—Kidō formulas, body coordination, energy flow. That's why no one dares switch. But if you do… your Shunkō will not just be complete. It will be perfect."
Suì-Fēng looked down, her sharp features hardening into determination.
Renya, however, felt his chest tighten. He thought of her future—the battles ahead, her desperate clash with the Segunda Espada Baraggan, her final stand against the Sternritter. Every memory overlapped with the woman standing before him now, resolute and unyielding.
Why do I want her to be stronger so badly?
Watching her, he realized the answer lingered quietly in his heart. He thought of Yoruichi's black cat form and smirked faintly.
"Maybe I should raise a cat myself," he muttered under his breath. "Though mine would be white. But there's a saying: whether black or white, as long as it belongs to you, it's a good cat."