Sister-Con Activated: The Sun Breathing Style Hits Whatever I Point At

[Demon Slayer Fanfic + Ancestor-Era Transmigration + Younger Tsugikuni Sister + Tsugikuni Yoriichi + Tsugikuni Michikatsu + System as a Temporary Patch Only + Sacrificial Transmigration + No Romance + Siblings Focus + Choices and Saving Lives + Target Length: 300,000 Words]

A journey adrift across the ages, from the Warring States period to the Taisho era, began with a transmigration gone wrong.

With the Transparent World and Demon Slayer Mark sealed away, he saw his younger sister's true appearance clearly for the first time.

In the aftermath of a chaotic age, the siblings relied on each other, fighting demons with their blades and keeping each other close.

The tragedy of kin turning against kin remained etched in their minds. Their once-beloved elder brother had become a demon, an unhealed wound between them.

Hesitation, pain, and obsession took root, but they always had each other by their side.

The road ahead was long, their blades ever at their sides. All they wanted was to cross the darkness and bring back the brother they once knew.

With family as their vessel and bonds as their oars, they set out together on a long-delayed journey of redemption.