The Phosphor Trench of Miyabi

In a vertical abyss of four nested hollow worlds connected by a titanic central drop-shaft, soaring wind currents and planetary barometric pressures dictate the laws of sail, ballistics, and survival. Fleets plunge across vacuum voids under full canvas, propelled by baric pyrodynamics—heavy iron mortars firing concussive charges of black powder spiked with deep-sea squid marrow to anchor ships to descending gravity lines. But from the black floor of the lowest hollow sphere, a cold phosphorescent miasma is ascending through the shafts. Wherever the phosphor fog touches gunpowder, munitions transform into swarming, chittering vermin that devour rigging and fuse gunners to their iron. As the civilized upper spheres shatter into paranoid purges and desperate naval raids over uncorrupted powder magazines, four souls caught across the war machines—bombardier captain Tomoki, trench dredger Natsue, citadel inquisitor Kazuma, and penal surgeon Ryosei—must navigate escalating mutinies and anatomical nightmares, blind to the terrifying truth that the rising phosphor is not an accident of nature, but the planetary immune system waking up to eradicate them all.