The taste of Rimuru's slightly-burnt-but-made-with-love birthday cake still lingered pleasantly in Lucy's memory as the new phase of her training began. The magnificent sword, 'Starlight Requiem' as she'd whisperingly named it, felt like an extension of her arm, and the divine keys of Sol and Luna hummed with a comforting warmth against her hip. For the first time since that terrible day, a genuine, unforced lightness had touched her heart.
"Alright, Lucy!" Rimuru declared a few days after her ninth birthday, his voice echoing with an almost boyish enthusiasm through their familiar forest clearing. "We've built up your body, honed your blade skills to a terrifying edge – seriously, you're scarier than some veteran knights I knew – and now, it's time to fully awaken the magic slumbering within you! Today, we dive deep into Celestial Spirit Magic!"
Lucy's blue eyes, usually so intense during training, sparkled with a rare, bright eagerness. She clutched Sol's golden key, its solar radiance seeming to pulse in time with her excited heartbeat. "Yes, Sensei! I'm ready!"
"Let's start with Sol. Focus, Lucy. Feel the Ethernano in the air, in your own body. It's all around you, a vast ocean of energy. Your magic is the tap, and the key is… well, the key!" Rimuru grinned. "Reach out with your heart, with your will. Call to him."
Lucy nodded, her small face scrunched in concentration. She closed her eyes, took a deep breath, and raised Sol's key. The air around her shimmered. "Open! Gate of the Sun! I call upon thee, Sol!"
A pillar of incandescent golden light erupted, bathing the clearing in a warmth that chased away the morning chill. Sol materialized, his golden hair flowing like solar flares, his amber eyes fixed on Lucy with a gentle respect. "Lucy-sama. The Sun answers your call." His voice was like the rumble of distant, benevolent thunder.
"He's… he's incredible, Sensei!" Lucy breathed, her eyes wide with awe. She felt a connection to Sol, a warmth that spread through her, comforting and empowering.
"He is indeed!" Rimuru chuckled, looking immensely pleased. "Now, try giving him a simple command. Nothing too strenuous. Maybe… ask him to light up that old, dead tree over there?"
Lucy turned to Sol. "Sol… could you, um, make that tree shine?"
Sol inclined his head. "As you wish, Lucy-sama." He raised a hand, and a beam of concentrated sunlight, no thicker than Lucy's wrist, lanced out, striking the dead tree. It didn't burn; instead, the wood began to glow from within, bathed in a soft, golden luminescence.
"Wow!" Lucy gasped.
"Excellent control, Sol!" Rimuru praised. "And you, Lucy! You're a natural! Your connection is strong already!"
They practiced with Sol for an hour, simple commands, maintaining the summoning, feeling the flow of magical energy. Lucy's initial nervousness gave way to a quiet confidence. Then, they moved on to Luna.
"Open! Gate of the Moon! I beseech thee, Luna!"
The silvery light was a stark contrast to Sol's brilliance – cool, serene, mystical. Luna appeared, her starlight gown shimmering, her moon-like eyes filled with a gentle wisdom. "Lucy-sama. The Moon is with you."
Luna's magic was different. Where Sol's was direct and radiant, Luna's was subtle, intuitive. At Rimuru's suggestion, Lucy asked Luna to reveal any hidden creatures in a patch of dense undergrowth. Luna raised a delicate hand, and shimmering motes of silver light drifted into the bushes, outlining the forms of startled rabbits and a curious fox, their eyes glowing faintly in the ethereal light.
"They're so different," Lucy murmured, looking between where Sol had stood and where Luna now graced them. "But… they feel… connected. Like two sides of the same beautiful coin."
Rimuru smiled softly. "Exactly, Lucy. Balance. Power and grace. Now, try summoning them both. It'll be a strain, but I think you can manage it for a short while."
With a deep breath, Lucy focused, pouring her will into both keys. "Open, Gates of Sun and Moon! Sol! Luna!"
VWOOOSH! The clearing was filled with a breathtaking interplay of golden and silver light. Sol and Luna stood side-by-side, their energies harmonizing, creating an aura of immense, balanced power that made the very air hum. Lucy felt a significant drain on her reserves, but also an exhilarating surge of strength.
"Incredible…" Rimuru breathed, genuinely impressed. She's handling their combined divine presence better than most seasoned mages could handle a single high-tier spirit! This kid…
After a few minutes, Lucy, panting slightly, dismissed them. "That was… a lot, Sensei."
"But you did it!" Rimuru beamed. "Fantastic! Now…" His expression shifted, becoming a little more thoughtful. "You mentioned your mother, Layla, left you her own Celestial Spirit keys, didn't she? The Zodiacs?"
Lucy's bright smile faltered, the light in her eyes dimming almost imperceptibly. She reached into her satchel and slowly pulled out the ornate wooden box. Her fingers trembled slightly as she opened it, revealing the golden keys of Aquarius, Cancer, and Taurus. "Yes, Sensei."
"Those are powerful spirits, Lucy," Rimuru said gently. "Aquarius, especially. Have you… tried summoning them since…" He trailed off, not wanting to push.
Lucy stared at the keys, her gaze distant. A shadow crossed her face. "I… I tried with Aquarius, once. A long time ago, when Mama first gave her to me. She… she was really mean, Sensei." A flicker of old fear, of a child's hurt, crossed her features. "She yelled at me a lot. And… and now…" Her voice dropped to a whisper, laden with a sorrow that made Rimuru's heart ache. "Looking at them… using them… it feels like… like I'm disturbing Mama's memory. They were hers. It… it hurts too much right now."
Rimuru's expression softened with understanding. He knelt beside her, his voice gentle. "Hey, it's okay, Lucy. There's no rush. Magic, especially Celestial Spirit magic, is about the bond, the connection. If you're not ready, forcing it will only make things harder for you and the spirits." He placed a reassuring hand on her shoulder. "We can focus on Sol and Luna for now. They're more than enough power for any situation. And hey," he added, a thoughtful glint in his eye, "if down the line you feel you need a different kind of spirit, something specific for a particular task, and you're still not feeling up to using your mother's keys… well, I'm pretty handy with crafting these things, you know. I could probably whip up another unique key for you, custom-made. How's that sound?"
A tiny, watery smile touched Lucy's lips. The knot of anxiety in her chest loosened slightly. "You… you'd do that, Sensei?"
"Of course, I would!" Rimuru said warmly. "Anything for my star pupil!"
The following weeks saw Lucy's mastery over Sol and Luna grow exponentially. She learned to weave their powers together, Sol's fierce solar blasts complemented by Luna's subtle illusions and defensive barriers. Her swordsmanship became even more potent, imbued now with flickering solar fire or shimmering moonlight. Rimuru watched, a mixture of pride and a strange, burgeoning awe filling him. She was a whirlwind, a prodigy, a force of nature in the making.
But as her power grew, so too did an underlying intensity, a cold fire that sometimes flickered in the depths of her blue eyes when she thought he wasn't looking.
One sweltering afternoon, after a particularly dynamic session where Lucy had seamlessly combined a flurry of sword strikes with a miniature solar flare from Sol to disarm a practice dummy Rimuru had animated, he clapped his hands together, his expression turning unusually stern, though a playful spark still danced in his eyes.
"Alright, Lucy, you're getting scarily good with the finesse! But true strength isn't just about flashy moves; it's about endurance! About pushing past your limits when every fiber of your being is screaming at you to stop!" Rimuru announced, his voice taking on a theatrical drill sergeant's bark. "Today, we test those limits! We're going to find out just how deep your well of stamina and willpower truly goes!"
Lucy, her breath coming in steady pants, her brow furrowed in concentration, nodded, her grip tightening on Starlight Requiem. Sol and Luna's keys glinted at her belt, warm against her skin. "Yes, Sensei. I'm ready."
"Warm-up time!" Rimuru boomed, trying to inject some levity, though he had a specific goal in mind. He wanted to see how she'd react under extreme physical duress before adding magical strain. "Let's start with… five hundred push-ups! Five hundred sit-ups! Five hundred squats! Then, a five-mile run through the roughest terrain in this forest, carrying that weighted pack over there!" He pointed to a heavy-looking pack he'd prepared earlier. "Think you can handle it, champ?"
Lucy's eyes, usually so expressive, seemed to glaze over for a fraction of a second, a chilling focus settling over her features. There was no hesitation, no complaint, no visible sign of fatigue from their earlier sparring. Just a curt nod. "Understood, Sensei."
Rimuru blinked, his own boisterous facade faltering. Okay, five hundred is still a lot for a nine-year-old, even one trained like her, he thought, a flicker of unease touching him. But she's not even batting an eye? Not even a dramatic sigh for my benefit? This kid… she's becoming something else entirely. He tried to match her sudden intensity, though his drill sergeant act felt a little hollow now. "Alright, then! Let's GO! GO! GO!"
Lucy began. Her movements were precise, powerful. Each push-up, each sit-up, each squat was executed with a mechanical perfection that was almost unnerving. Rimuru watched, his initial attempts at loud encouragement ("Feel the burn, Lucy! That's the feeling of GETTING STRONGER!") slowly dwindling into a stunned, disbelieving silence.
She's… she's actually doing it, he thought, his mind reeling as she moved from one exercise to the next without so much as a pause for breath. And her form… it's not degrading. At all. It's like she's running on… on something else. Not just muscle and stamina. He saw her knuckles whiten as she pushed through the last hundred squats, her jaw set so tightly it looked like it might crack. A faint tremor ran through her shoulders, the only outward sign of the immense strain.
When she finally finished the calisthenics, there was a sheen of sweat on her brow, but her breathing, while deep, was still remarkably controlled. She moved to the weighted pack, hoisted it onto her small back with a grunt that was more air escaping than a sound of effort, and then, without a word, she sprinted off into the dense, unforgiving forest.
Rimuru just stared after her, a cold dread beginning to coil in his stomach. This isn't just talent anymore. This isn't just willpower. This is… this is something darker. He remembered his earlier fears, his desire to give her a better story. But what story was she writing for herself with this terrifying, all-consuming drive?
An hour later, Lucy returned. She wasn't sprinting, but her pace was still relentlessly brisk. She dropped the pack with a dull thud, the ground vibrating slightly. Her face was flushed, her hair plastered to her forehead with sweat, but her eyes… her eyes were like chips of ice, cold, focused, and utterly devoid of the warmth, the childish spark he was so used to seeing, so cherished.
"Magical strength training next, Sensei?" she asked, her voice flat, almost devoid of emotion, each word clipped.
"Uh… yeah. Yeah, sure," Rimuru stammered, the sight of her chilling him to the core. He gestured weakly towards the practice targets they'd set up – massive boulders and thick, reinforced trees. This is where it'll show, he thought with a sinking heart. If she's drawing on that darkness, her magic will reflect it.
Lucy nodded once, then turned to face the targets. She raised Sol's key. "Open, Gate of the Sun! Sol!" Her voice was no longer a call; it was a command, sharp and unyielding. Sol appeared, his usual gentle radiance subtly dimmed by the sheer intensity emanating from his summoner.
"Destroy them," Lucy ordered, her voice a low growl.
Sol hesitated for a micro-second, his amber eyes flickering towards Rimuru with something akin to concern, before obeying. Beams of solar energy, far more concentrated and destructive than any Lucy had commanded before, blasted into the boulders, not just cracking them, but vaporizing chunks, sending superheated rock fragments flying. Then came Luna, her silver light taking on a cutting, almost cruel edge as ethereal moonblades sliced through reinforced trees as if they were parchment. The air crackled with raw, untamed power. Lucy's magical energy, which had been steadily growing, had taken a monstrous, terrifying leap, fueled by something primal and harsh.
"Lucy," Rimuru finally managed to say, his voice laced with a concern he couldn't hide, stepping closer as she dismissed her spirits, her chest heaving but her eyes still holding that unnerving, frozen glint. "Why? Why are you pushing yourself this hard? This is… this is beyond anything I intended for today's training. This is… too much."
Lucy slowly turned, her intense gaze locking onto his. The coldness in her eyes seemed to deepen, hardening into something akin to polished obsidian. "I remember it all, Sensei," she said, her voice a low, dangerous whisper that sent an involuntary shiver down Rimuru's spine, despite his own immense power. "Every single day. Every night. It replays in my head when I sleep, when I wake, when I train. It never stops."
"Remember what, Lucy?" Rimuru asked, his voice soft, a profound dread coiling in his stomach, though he already knew the answer. He'd hoped… he'd hoped he was wrong.
"I remember the sounds my mother made when they hurt her," Lucy said, her voice dropping further, yet each word was laced with a chilling, venomous clarity that cut through the humid air. "I remember my father's screams. I remember the exact shade of red as their blood pooled on our drawing-room floor. I remember the look in their eyes as the light faded, as they died right there in front of me, helpless." Her small fists clenched so tightly her knuckles were bone-white, trembling with suppressed fury. "I remember the faces of the scum who did it, Sensei. I remember their laughter as they tore our home apart."
Tears, hot and furious, began to stream down her face, but they did not soften the terrifying hardness in her eyes. They were tears of pure, unadulterated rage. "I remember every single, cursed detail. And I will kill them. I will find every last one of them, and I will make them suffer a thousand times what my parents suffered. Every. Single. Day. Until then… this pain, this training… it's nothing, Sensei. It's less than nothing."
Rimuru's eyes widened, his breath catching in his throat. He saw it then, blazing behind the tears – the raw, all-consuming inferno of her rage, an inferno fueled by an ocean of unspeakable grief and an insatiable, terrifying thirst for vengeance. The playful child he'd found, the determined student he'd nurtured… they were still there, somewhere deep inside, perhaps, but they were being systematically burned away, consumed by this monstrous, burning hatred.
She's not just training for strength anymore, he realized, his heart sinking with a profound sense of failure and a chilling fear. She's forging herself into a weapon. A living instrument of pure, unadulterated revenge. And I… I handed her the hammer and the forge.
He reached out, his hand trembling slightly, wanting to place it on her small, shaking shoulder, to offer some comfort, some guidance, anything to douse even a fraction of that terrible fire. "Lucy…" he began, his voice thick with sorrow and a desperate urgency, "I understand your pain, believe me, I do. More than you can possibly imagine. But this path… this burning hatred… it's a poison, Lucy. It will consume you. It will burn away everything good, everything bright, until there's nothing left but the ash of your anger."
Lucy violently shrugged off his touch before it could even land, her tear-streaked face contorted in a mask of defiant agony, her eyes still locked on his, cold, hard, and unyielding as frozen steel. "It's all I have left, Sensei," she stated, her voice flat, each word a shard of ice. "It's the only thing I want. Can't you understand that?"
Rimuru sighed, a deep, weary sound that seemed to carry the weight of millennia. He looked into those frozen blue eyes, into the inferno raging behind them, and he knew. He knew he couldn't change her mind. Not now. Not with words. The wound was too deep, the fire too all-consuming. He had hoped to guide her, to give her a future filled with light. But the darkness of her past had too strong a grip.
"Alright, Lucy," he said, his own voice taking on a firm, resolute tone, a deep sadness settling in his ancient soul. He wouldn't abandon her. He couldn't. He had started this. He had to see it through, for better or for worse. "But you listen to me, and you listen well. True strength, the kind that lasts, isn't just about destruction. It isn't just for killing. It's about protecting what you cherish, what little light you can find or create in this often-cruel world. It's about having the power to choose your own path, Lucy, not just be blindly driven down one single, burning road by your pain. It's about making damn sure no one else ever has to suffer the way you did, the way your parents did."
Lucy merely nodded, her expression unreadable, though the tears had momentarily stopped, leaving glistening tracks on her dirt-streaked cheeks. Her eyes, however, remained as hard and unforgiving as diamonds. "I understand, Sensei." But did she? Did she truly?
Rimuru looked at the small, immensely powerful, and terrifyingly resolved girl standing before him. The setting sun bled crimson across the sky, casting long, ominous shadows that seemed to writhe and dance around them, a cold wind rustling the leaves, whispering secrets only the dying light could hear. He had wanted to give her a better story. He had wanted to fix this broken timeline. But as he looked into the chilling depths of her vengeful gaze, a question, cold and sharp as any blade, pierced his heart, a question he couldn't bring himself to voice aloud, a question that would haunt his immortal existence:
"By giving you this power, Lucy… by trying to make you strong enough to face any darkness… have I merely unleashed a greater one upon this world, and upon yourself?"