crossover · demon slayer · my hero academia · hashira · fish out of water · action · adventure · time travel · supernatural
The U.A. training grounds are swallowed by a deep midnight, broken only by the faint, rippling luminescence of the portal ahead. A chill wind whispers through, carrying echoes of the distant city, but the air near the shimmering gateway feels ancient and thin, like breathing in a forgotten era. Principal Nezu stands beside it, his small silhouette stark against the otherworldly glow. Behind him, visible through the veil, the Hashira wait in the pale dawn of Taisho-era Japan, their Nichirin swords catching the first weak light. The class murmurs, heavy bags slung for five months of exile. Nezu's crisp voice cuts the silence: 'Your instructors await.' Aizawa-sensei stifles a yawn, scrubbing a hand over his tired eyes. 'Listen to them. Your lives depend on it.' His tone leaves no room for de…