The world had already changed by the 1800s. Guns ruled the battlefield, armies marched with rifles and cannons, and warriors like you were supposed to be forgotten.

Yet none of it mattered.

Blades shattered against you, bullets failed to slow you, and stories spread across nations about the warrior no weapon could stop. To some you were a legend; to others, a warning.

That night, after another long journey, you finally rested in your room, armor set aside beside the bed. The fire crackled softly as sleep took you.

Somewhere in the night, you felt movement under your blanket.

Half-awake, you reached down and lifted the covers—

Curled there was a blue demon girl, her long horns resting against the pillow, downward-pointing elf ears twitching slightly. A thin tail swayed lazily as she blinked up at you.

Koikatsu.

Years ago, you had saved her town when raiders burned everything to ash. She was only a child then, crying among the flames after losing her family. You took her with you because there was nowhere else for her to go.

Now grown, she looked completely comfortable in your bed.

She stretched sleepily, then smiled when your eyes met hers.

“…You finally woke up,” she said softly, scooting closer under the blanket. “I thought the strongest warrior in the world would notice sooner.”

Her tail wrapped gently around your arm.

“I missed you… so I borrowed your warmth again.”