A full month had passed since Keith awakened the Sign-In System.
The night was quiet, the moonlight pouring gently into his room. Keith sat on his bed, legs crossed, eyes closed calmly.
"System," he said in his mind, "activate the monthly sign-in."
[Affirmative, Host.]
A soft chime echoed in his consciousness.
[System Notification: Host's First Monthly Sign-In Successful.]
[Rewards Granted:]
— Yamato (Devil May Cry)
Keith's eyes shot open.
"Yamato… Vergil's sword…?" he whispered, breath catching in excitement.
A DMC-level mythical katana.
A blade that cuts space.
A weapon capable of slicing dimensions themselves.
His heart raced.
"Claim reward," Keith whispered.
A faint light shimmered before him, forming into a long, elegant katana resting across his lap. Its black scabbard gleamed, the silver edge softly humming as if alive.
Keith wrapped his fingers around the hilt and slowly unsheathed it.
Shing—
A soft, clean, ethereal sound filled the room.
In that moment, Keith felt a pulse—like the sword was greeting him.
A faint warmth spread through his hand, and Keith smiled.
"It… acknowledged me."
He gently traced the edge, admiring the blade's flawless beauty. Yamato felt weightless yet heavy with power, peaceful yet dangerous beyond comprehension.
Just then—
The door slammed open.
"KEITH!"
Luna marched in, her amethyst eyes sharp and panicked. Then they widened.
She rushed to him immediately.
"What do you think you're doing holding a weapon in your bedroom?! You scared me—what if it fell, what if it cut you—Keith!"
Keith flushed, caught red-handed like a child with stolen sweets.
"S-Sorry, Luna… I didn't think you'd come in right now."
Luna glared at him, arms crossed—with the terrifying aura of an older sister and fiancée combined.
"Give me that," she ordered.
Keith sheepishly handed her Yamato.
Luna held the katana with surprising delicacy. She examined every inch of the blade, the scabbard, the guard.
Her eyes grew amazed, fascinated, and slightly starstruck.
"This sword…" she murmured softly. "It's… unbelievable. It feels… alive."
Keith nodded. "It's called Yamato. A legendary blade from a story in my previous world—Devil May Cry. It can cut space itself. Vergil used it."
Luna turned toward him slowly, eyes gleaming.
"This is incredible. This weapon… Keith, it suits you."
Her admiration turned into something softer.
Then—
Her expression shifted entirely.
"Keith," she said with the tone of someone making a serious request, "if you ever get another sword like this… anything even remotely similar…"
She leaned closer.
"…save it for me."
Keith nodded without hesitation, smiling.
"Of course. If anything matches your sword style, I'll give it to you first."
Luna's expression softened into warmth.
She sheathed Yamato with a clean click and handed it back.
Keith stored the blade into his system inventory with a thought.
"Alright, it's put away—"
He didn't get to finish his sentence.
Without warning, Luna's eyes turned mischievous.
She took a few steps back, then—
jumped onto the bed.
"L-Luna—?"
Before Keith could react, Luna wrapped herself around him tightly like a protective serpent.
He let out a small gasp as she pulled him flush against her.
"Luna—!?"
She nuzzled into his neck, her voice soft and sleepy.
"No more weapons tonight," she murmured. "Just you."
Keith blinked rapidly, his face turning crimson.
But Luna simply tightened her arms around him possessively, her breathing slowing.
Within moments, she was asleep—holding Keith like he was the most precious treasure in the world.
Keith sighed softly.
"…Why do I even try?"
Yet he didn't push her away.
He adjusted himself into her embrace, feeling the warmth of her body and the peaceful quiet of the night.
And gradually, Keith drifted into sleep as well—safe in the arms of the Swordmaster's prodigy.