Shadow Slicing Shortsword (item)

Shadow Slicing Shortsword can be picked up at the Phasing Korthian Shrine on the westernmost floating island off the edge of Korthia. At revered (revered) with the Archivists' Codex, purchase and use the Research Report: Ancient Shrines, then interact with the shrine, reach the altar, start the quest Shadow Slicing Shortsword, then get back to safety before time on the buff runs out.