The next day, Leo acted like absolutely nothing had happened.
Then again, nobody had seen him literally eat a small Oni.
Right now, he was back to sparring with Asagi again — the young prodigy who still believed this time she could beat him.
Spoiler: she couldn't.
Still, Leo gave her credit. She was faster than yesterday, sharper too. Every strike carried that fiery "I'll show you!" energy that he'd grown to expect.
'Gotta hand it to her,' Leo thought as he blocked another swing. 'Girl's pride is made of titanium.'
What Asagi didn't know, though, was that Leo had gotten a tiny power-up since their last match. After all, eating an Oni's biomass — as horrifying as that sounded — came with perks.
He could feel it in his muscles: a bit more strength, a bit more speed, and a lot more stamina.
As if a six-year-old kid needed any more of that.
Meanwhile, on the other side of the training yard, Sakura and Tokiko were watching the spar from the shade of a nearby tree.
Sakura tilted her head, squinting at Leo as he effortlessly blocked Asagi's strikes.
"Hey," she muttered, leaning closer to Tokiko, "did your cousin get stronger or something?"
Tokiko blinked, following Leo's movements with a puzzled look. "...Yeah. He's moving way faster than yesterday."
Sakura crossed her arms. "Great. Asagi's gonna hate that."
Tokiko nodded slowly, whispering like she was watching a disaster unfold in real time.
"She's totally gonna blow a fuse."
Then, both girls froze when a sharp scream echoed across the yard.
"Why won't you let me hit you!" Asagi yelled, her voice full of frustration.
Leo blinked, still holding his wooden sword casually against his shoulder. "Because," he said, tone calm and annoyingly patient for a six-year-old, "you keep leaving your guard open every time you swing from the left."
Asagi's eye twitched. "Stop analyzing me like an old man!"
Sakura and Tokiko exchanged looks, then quietly backed up toward the fence.
"...Yup," Sakura whispered, "she's about to lose it."
Tokiko nodded. "Should we stop them?"
Sakura grinned. "And miss this? No way."
Asagi gritted her teeth, gripping her wooden sword tight. "You think you're so smart, don't you!?"
Leo sighed, scratching his head with his free hand. "No, I just think you should—"
"DON'T SAY IT!" she screamed, cutting him off as she dashed forward, her movements faster than before.
Sakura and Tokiko leaned in from the fence, whispering like sports commentators.
Sakura: "Oh, she's mad mad."
Tokiko: "Yup. She's going for a full swing."
Asagi leapt, twisting in mid-air, her sword coming down toward Leo's shoulder. It was fast—faster than before—but to Leo's eyes, it was almost slow motion.
'Guess the Oni's biomass did more than I thought,' he mused.
He raised his wooden sword and parried gently. Crack!
The moment the swords met, Asagi's weapon snapped in half. The shockwave knocked her back a few steps, her eyes wide.
Sakura and Tokiko blinked in silence.
"…She's gonna cry, isn't she?" Tokiko whispered.
Leo's expression went pale as he realized what just happened. "Oh crap." He dropped his sword, ran to her, and crouched down. "Asagi, are you okay? I didn't mean—"
"YOU BROKE MY SWORD!" she shouted, cheeks puffed up and eyes glossy with tears.
'Yup. There it is.'
Asagi's bottom lip trembled. "That was my favorite sword!"
Leo held up his hands. "It was an accident! I didn't even swing hard—"
"That makes it worse!" she snapped, stamping her foot. "You're mocking me!"
Sakura whispered to Tokiko, "Oh no… she's entering the drama arc."
Tokiko nodded solemnly. "Pride damage critical."
Leo rubbed the back of his neck. "Alright, fine. You can hit me back."
Asagi blinked. "What?"
"I'll stand still. One free hit. Make it count."
That made Sakura gasp. "He's crazy."
Asagi's eyes gleamed like someone had just handed her divine vengeance on a stick. "You said it!"
Leo braced himself, closing his eyes. "Go ahead—just not the face—"
THWACK!
She smacked him square in the shoulder with the broken half of her sword. Not even hard enough to hurt, but she puffed up proudly like she'd slain a demon king.
"There," she said with a huff. "We're even."
Leo grinned, rubbing the faint red mark. "You hit like a real samurai."
Asagi's pout faltered. "...You're not mad?"
He laughed. "Nah. Pride's important. Just don't let it blind you."
Sakura: "Wow. He's like, wise and stupid at the same time."
Tokiko: "That's his whole personality."
Asagi blinked at him, her expression softening before she crossed her arms again. "…Fine. But next time, I'm winning."
Leo smiled. "Looking forward to it."
He looked at Asagi seriously, lowering his wooden sword.
"Asagi, I just wanna say something."
She blinked. "What is it?"
He smiled faintly, that mix of awkwardness and sincerity written all over his face.
"Listen… you probably think I'm just bullying you during training."
Asagi opened her mouth to protest, but Leo raised a hand, cutting her off.
"But I'm not. You're my fiancée — Mom and Dad told me that means we'll be together in the future." He hesitated for a second, then met her eyes again. "So… if you're gonna get stronger, then I'll get strong with you. To protect you."
For a moment, silence hung between them. Asagi's cheeks turned pink as she stared at him — wide-eyed, unsure how to react.
Leo, meanwhile, internally screamed:
'Okay, which dating sim script did I just rip that line from?!'
Asagi froze, then turned away so fast her ponytail nearly hit him.
"W-Who said I needed protecting?! Don't say embarrassing stuff like that!"
Leo just grinned. "You didn't say I was wrong, though."
She stomped her foot. "Th-that's not the point!"
Up by the fence, two small heads peeked through the slats — Sakura and Tokiko, watching like gossip reporters.
Sakura whispered loudly, "Oh my gosh, they're so sappy!"
Tokiko nodded solemnly. "She's blushing so hard she looks like a tomato."
"Shut up, you two!" Asagi snapped, pointing the broken sword at them.
The younger girls ducked down, giggling.
"Totally her boyfriend," Sakura whispered.
"Fiancé," Tokiko corrected.
"Same thing!"
Asagi turned back to Leo, cheeks puffed out. "You—! You heard that!?"
Leo smiled, calm as ever. "Yup. And I'm pretty sure the whole neighborhood did too."
She groaned, burying her face in her hands. "I hate all of you."
"Love you too," Leo said lightly, walking toward the dojo exit.
Asagi peeked through her fingers, still red-faced, while Sakura and Tokiko popped their heads back up to exchange synchronized thumbs-ups.
"Mission accomplished," Sakura whispered.
"Operation: Make Asagi blush — success," Tokiko added.
Leo, pretending not to hear, smirked to himself.
'Yup,' he thought, 'somewhere out there, fate's crying because I'm rewriting the whole timeline into a rom-com.'
Asagi pouted in the corner while Sakura and Tokiko giggled behind the fence.
Leo glanced between them, sighing. "Y'know, for a bunch of six-year-olds, we sound way too mature."
Sakura shrugged. "We live in Japan's demon capital. You grow up fast."
Tokiko added cheerfully, "Plus, my dad says taxes are worse than demons!"
Leo blinked. "…Yeah, that explains everything."
He stood, brushing off his pants. "Alright, future war heroes — training's over. Go play tag before someone declares another duel."
Aoi Fuuma stood in front of the small group of children, hands on her hips, eyes bright with energy. Even though her students were barely taller than the practice blades beside them, she spoke with the same enthusiasm she used when teaching full-grown trainees.
"A Ninja Art," she began, voice rising theatrically, "is the supernatural power that Taimanins can create! It's unique to each user — some control fire, others lightning, some even bend shadows themselves!"
The group's eyes widened, and a few gasps escaped the kids. Sakura practically bounced in place, while Asagi tried to keep her composure, arms crossed but her curiosity giving her away.
Aoi continued, pacing in front of them like a storyteller. "These Arts aren't magic like what demons use, nor are they the spiritual techniques of Onmyoji. Ours are special — Taima particles! They disrupt demonic power and make our attacks far more destructive to demon cells than normal weapons."
Leo raised his hand. "So basically... it's like anti-demon science?"
Aoi blinked, then grinned. "Exactly! My clever boy gets it!"
Sakura leaned toward Tokiko and whispered, "I still think it sounds like magic with extra steps."
Tokiko nodded. "Cooler name, though."
Aoi clapped her hands. "Combination attacks between skilled Taimanins can even harm noble demons — the ones that seem immortal. But—" she raised a finger, suddenly serious, "—a Ninja Art isn't just about raw power. It's about control, focus, and heart."
Leo thought quietly to himself, So it's like a mix between ki and anti-virus energy... Guess I'm gonna need to study hard if I don't want to explode the first time I try it.
Aoi smiled at the group, her tone softening. "Remember, children — the heart of a Taimanin isn't hatred. It's courage. That's what makes our Arts shine."
The kids nodded, wide-eyed. Even Asagi seemed caught up in the moment, her earlier pride giving way to a rare expression of awe.
Aoi clapped once. "Alright! Enough talk — let's see what you can do with basic concentration exercises! Sit down, close your eyes, and feel the flow of Taima within you!"
Leo sat cross-legged with the rest, breathing slowly, but his mind drifted.
Taima particles, huh? Wonder if my Biomass reacts to that… hopefully it doesn't turn me into a glow stick.
She then spoke as she looked at the kid. "Oh, one more thing, Arts fall in some overarching categories like elemental (Fire, Water, Wind, Earth, Wood or Metal), and Exelemental. (Beast, Beast Tamer, Paper, Puppet, Soul, Void). For example, "Explosion Art" could be a subsection of Fire or Wind Art or its own Elemental type".
Aoi gestured with both hands as if painting invisible symbols in the air. "So remember, children! Each Ninja Art manifests differently depending on the user's affinity and imagination. Two Taimanins with Fire Art may use it completely differently — one might forge blazing weapons, while another breathes fire like a dragon!"
Sakura's eyes sparkled. "Can I make fire that's pink?"
Aoi chuckled. "If your heart burns pink, my dear, then maybe you can!"
The kids giggled at that, but Leo sat quietly, deep in thought.
'Water Art… yeah, that'd be perfect,' he mused. 'If I can master that, I might be able to recreate the breathing techniques from Demon Slayer. Imagine that — combining Taima energy flow with controlled respiration. Maybe even amplify my Biomass control with it.'
He smirked faintly to himself.
'James Heller would probably call me a nerd, but hey — I'll be a nerd who can decapitate demons artistically.'
Aoi clapped her hands again. "Alright! Focus time! Everyone close your eyes and breathe deeply. Feel for the warmth — or chill — that responds when you focus inward. That's your affinity trying to answer you!"
The children obediently shut their eyes, though Sakura peeked once to check if Asagi was doing it right. Asagi sat perfectly still, serious as ever, while Tokiko was already dozing off.
Leo, meanwhile, felt… something. Not warmth. Not chill.
It was a pulse — faint, thrumming beneath his skin. A living, shifting thing.
'That's not Taima energy… that's my biomass.'
He focused harder, trying to sense both energies — the alien hum of his mutation and the subtle shimmer of Taima particles around him. For a brief moment, the two resonated — and he felt an intense jolt up his arm, his veins flashing faintly red and blue.
Aoi's eyes widened. "Leo? Are you alright?"
He blinked rapidly, shaking it off. "Y–Yeah! Just… felt a weird spark, that's all!"
Aoi tilted her head, curious but smiling gently. "Hmm… seems like my little prodigy might have quite the strong reaction to Taima already."
Leo chuckled nervously.
'Or it's my alien virus fighting holy magic energy inside me. No big deal.'
Leo's fingers twitched as that strange pulse lingered under his skin — the alien, hungry rhythm of something alive inside him.
'If James thinks I'm neard… what will Alex think of this?' he wondered. 'Would he see me as an equal… or as competition?'
The thought made him shiver. For a moment, he could almost feel Alex Mercer's cold stare — the calculating kind that stripped you down to molecules.
'No… I'm not him,' Leo told himself firmly, clenching his fist. 'I'm not the virus. I'm just… borrowing it.'
The faint glow of Taima energy around him flickered, almost reacting to his turmoil — a gentle blue aura that clashed subtly against the dark red lines beneath his skin.
Aoi blinked, watching the faint light swirl around her son. "Fascinating… your energy's unstable, but powerful. You might have dual affinity potential, Leo."
Leo forced a small grin. "Guess I'm just special, huh?"
Inside, though, his mind was racing.
'Dual affinity? No, Mom… it's more like I've got two monsters arguing over my soul.'
To be continued
Hope people like this Ch and give me Power stones, also this is the last Ch for this week, expect 3 Ch per week for this fic
Also I have added Liliana into the harem, because I forgot to add her original
[Insert image of the Character here]
For people that want more girls in Leo's Harem put there pictures here if they get 50 likes I will add them