A Diresword is an Eldar Power Weapon only wielded by Exarchs of the Dire Avengers Aspect. These one-handed, single-edged Power Swords are crafted in the Eldar style, into which a potent Eldar spirit has been placed through the incorporation of a Spirit Stone into the blade. Any target wounded by a Diresword can be killed outright by the spirit residing within the Spirit Stone. When a blow is struck, the spirit within the sword will attempt to destroy the enemy's mind, potentially killing them instantly. This action is similar to the Imperial Nemesis Force Weapons used by psykers like the Grey Knights. The Phoenix Lord Asurmen carries the very first Diresword, the Sword of Asur. It contains the soul of his brother Tethesis, who was slain by a daemon, which allows the ancient Eldar hero to continue to fight against the greatest enemies of his people.
- Codex: Eldar (6th Edition), pp. 56, 64
- Codex: Eldar (4th Edition), pp. 30, 55
- Codex: Eldar (3rd Edition), pp. 34, 41-42