Erika let out a long, stunned "Ehhhhhhhhhh!" at what Akira said.
She quickly lifted her head and asked, her voice flustered, "What do you mean by that?"
Akira hesitated, his expression turning uncharacteristically complicated. "Well… the thing is…" He paused, searching for the right words. "…how should I put it…"
Then he took a deep breath. When he looked at her again, his eyes were serious, unusually so.
"I want to know how it feels to do that," he said. "Not you hugging me while drinking my blood. Not hugging while flying. Not anything like that. Just… hugging. Can we do that?"
This time, Akira didn't use any of his usual secret techniques, no puppy eyes persuasion. There was only sincerity in his eyes.
Erika looked at him, truly looked at him, and realized how rare it was for him to be this serious about something. That only confused her more.
Still, after a brief pause, she nodded and said quietly, "Fine."
Akira smiled, gentle and relieved, and pulled her into a hug as they lay down together. After that, the two of them remained there in silence for a while, simply lying together, neither of them saying anything.
Akira's face remained calm, his eyes closed as if he were thinking about something, or perhaps trying to feel something he couldn't quite grasp yet. He lay there quietly, focused inward, searching for whatever it was he was trying to find.
Erika, meanwhile, was panicking on the inside. "What's gotten into him lately? she thought. Why is he on the offensive so much…?"
With no idea what to do, she reached out to the only person she could ask for help.
"Selena…" she called telepathically.
"I've analyzed my brother's recent behavior", Selena replied calmly. "And I've come to a conclusion. He's trying to understand what love is."
Erika's thoughts jolted. "W–What?"
"I once told him that if he wanted to find love, he'd have to discover it himself", Selena continued. "So I believe he's experimenting, trying to understand what love feels like. Since he's never felt it before, he's doing things to see if he experiences anything different. Like getting close to you".
Erika's mind went blank. "B–But… we're just childhood friends, right? We're not like that… not yet, right?"
There was a brief silence.
"Are you an idiot? What kind of childhood friends are as close as you two?" Selena finally screamed.
Erika's face burned red at that.
"Then… what should I do now?" she asked softly.
"Just stay quiet", Selena replied. "And enjoy the moment".
So Erika did just that. She stayed silent, gently resting against Akira's chest, closing her eyes as she tried to relax, listening to the quiet, and letting the moment pass as it was.
Silence settled over them.
And yet, for some reason, Erika couldn't relax.
It wasn't because she was flustered. It was because she had noticed something, something she had been trying not to think about for a long time.
She couldn't hear his heartbeat.
Akira no longer had a heart. He had lost it to save her.
The realization struck harder than she expected. Much harder.
The fact that she could no longer hear his heartbeat hurt more than she thought it would. Her vision blurred, and before she could stop herself, tears welled up and began to fall. She pressed her face lightly against his chest as she started to cry, silently at first, then in small, trembling breaths.
Akira felt something warm and wet against his chest and frowned in confusion.
"…Huh?" he thought. "What's this? Did she not have enough? Is she drinking blood straight from my chest now?"
"Idiot", Selena's voice cut in telepathically. "She's crying".
"What?" Akira shot back, startled. "Why?"
"Don't ask me. Ask her".
Akira stiffened slightly and spoke softly. "Erika… are you crying? What happened?"
Still crying, Erika finally spoke, her voice shaking. "I'm… I'm sorry… because of me… your heart is gone…"
She had pushed it to the back of her mind for so long, refusing to think about it, refusing to face it. And now she realized something even worse.
She had never apologized to him. Not even once.
Akira froze for a moment, genuinely shocked. Then he laughed awkwardly and said, "Oh, come on. I'm fine now, right? I'm alive. I'm breathing. So don't feel bad."
"But your heart…" Erika said weakly. "It's gone."
Akira tilted his head, confused. "But I'm fine, though?"
"But…" Her voice broke again. "I want to hear your heartbeat… and now I'll never hear it again…"
Akira didn't understand.
"Why was she crying so much over this? Was a heartbeat really that important?"
In his previous life, there had even been a time when he seriously considered turning himself into a cyborg. To him, organs were just components, things that existed to make the body function. Losing one didn't feel like such a big deal.
But he also knew this.
Erika didn't see things the way he did; he was different, she was normal.
After thinking for a moment, Akira made a decision. He gently pulled her closer, guiding her against his chest, wrapping his arms around her more firmly.
"If you want to hear my heartbeat," he said quietly, "then I'll let you hear it. So… just stay here for a while longer. And be quiet, okay?"
He held her there, steady and gentle, as if preparing to show her something he himself had only recently begun to understand.
Erika didn't understand what he meant, but she did as he said. She lay quietly against his chest, her body tense, barely daring to breathe.
Akira closed his eyes.
"Brother, what are you going to do?" Selena asked telepathically.
"You'll see", Akira replied just as quietly.
With his eyes still closed, he focused inward, on something he had sensed a few times recently but had never consciously tried to grasp.
Erika remained still, listening.
At first, there was nothing.
No sound. No rhythm.
And then, she felt it.
A sound.
A steady, rhythmic thump… thump… thump.
A heartbeat.
Her eyes widened as she pressed her ear more firmly against his chest, afraid it might vanish if she moved.
"H–How…?" she asked softly. "Do you… have a heart now?"
Akira opened his eyes slightly. "No. That's not my heartbeat," he said calmly. "It's yours."
"Ehh…?" Erika froze. "What do you mean?"
Even Selena went silent for a split second before realization struck her.
"Brother, you…"
Akira continued, "That's your heartbeat."
"I'm… hearing my heartbeat… from you?" Erika asked, completely stunned.
"It's because of the Sacred Heart in my chest," Akira explained. "Lunar Vows. It activated."
"What… but what does it do?" Erika asked, still overwhelmed.
"I don't know much either," Akira admitted. "But for now… it can do this."
Erika slowly lifted her gaze to him.
Akira looked back at her and smiled gently. "I might have lost my heart," he said, "but I still have yours."
Erika's face instantly turned bright red.
From somewhere far away, Selena's voice exploded into his mind.
"WWWWOOOOW! Brother, where did you even get that line?!"
Akira very deliberately pretended not to hear her and kept his eyes only on Erika.
Erika, still lying against his chest, could clearly hear it now, the heartbeat growing faster and faster. She wasn't sure if it was hers or if it was something else entirely, but the sound filled her ears and her thoughts alike.
All she could see were his eyes, and she could hear that heartbeat.
The space between them grew heavy with tension, the quiet no longer empty, but alive.
Then, suddenly, Akira's body underwent a new transformation.
It was massive.
Huge enough that Erika felt it instantly.
Both of them froze.
The rising tension shattered in an instant, replaced by a completely different kind of rising tension, something impossible to ignore.
Without saying a single word, Erika slowly pulled herself away. She got up, walked to her own bed, lay down, and pulled the sheets over herself completely, hiding from the world.
Akira, just as silently, turned away. He covered himself with his own blanket and stared at the darkness, saying nothing.
Neither of them spoke.
And in that quiet, mutual agreement, they decided.
They would never talk about it.
Never again.
After that, the Hashira Training returned to a more normal rhythm as time went on. Nothing as serious or extreme happened again.
Akira and Erika trained alongside the Hashira and other Demon Slayers, steadily growing stronger. The days passed peacefully, aside from the occasional chaos caused by Akira chasing Sanemi and Obanai around to test his newest medicines.
Most of his time was split between intense training, working with Tamayo and Shinobu to advance Nezuko's treatment and develop new poisons, and joining various Hashira sessions simply to pass the time and sharpen his skills.
At present, Akira was having dinner in a small hut with Tanjiro, Inosuke, Genya, and several other Demon Slayers. They were all undergoing Gyomei's training. Zenitsu was there as well, but unlike his usual self, he remained quiet, still training elsewhere and not joining the conversation.
Just like in the original events, Kaigaku had encountered the Upper Moon one. However, unlike the anime's outcome, Akira's vaccine prevented him from turning into a demon, and Kaigaku died as a human instead. Because of that, the old Thunder Hashira did not have to die.
Zenitsu was clearly affected. He looked sad, but not broken. If anything, he seemed more determined than before. Akira didn't interfere. He had a feeling Zenitsu would find his own way forward.
As they ate, Tanjiro asked Akira about his adventures.
Akira talked casually about the many monsters he had fought, the strange places he had visited, and the countless battles he had survived. As the conversation continued, the topic eventually shifted.
"Werewolves?" Tanjiro repeated, tilting his head. "Is that like a demon?"
"No," Akira replied calmly. "Demons are altered humans. Werewolves are different."
He continued, "They're humans who transform into giant humanoid wolves on nights of the full moon."
Tanjiro's eyes widened. "Really?"
"Yes," Akira said. "And if a werewolf bites a human, and that human survives, they'll contract lycanthropy and eventually become a werewolf too."
Genya frowned. "What happens when someone turns into one?"
"Most of the time, they live as normal humans," Akira explained. "But on the night of the full moon, they lose control. They transform, and they kill everyone around them, friends, family, even lovers. When the night ends, they return to normal, often remembering everything."
Tanjiro's expression darkened. "That sounds cruel… I feel bad for them."
Inosuke suddenly leaned forward. "So which one's stronger, demons or werewolves?"
Akira thought for a moment. "It depends. Some werewolves are weaker than demons. But there are others…" He paused. "Some are far stronger than even the Upper Moons."
Everyone at the table froze.
Shock spread across their faces as the weight of his words sank in.
Time passed just like that.
Days flowed by in a steady rhythm of training, lighthearted moments, work, and quiet conversations. Despite the constant preparation and the looming threat of battle, there was a fragile sense of peace, one that no one spoke about, yet everyone felt. It was the calm they all knew would not last.
Then, one day, that calm was broken.
A man dressed like Michael Jackson stepped foot into the Ubuyashiki Mansion.