From Lexicanum

Nemesis force weapons are the characteristic weapon of the Grey Knights, and take the form of swords, axes, halberds, and hammers. Nemesis force weapons house a psi-matrix attuned to the unique psyche of its owner. The power of the weapon itself directly corresponds to the psychic talent of the wielder. In its original version, the haft incorporated a bolter weapon, similar to the Adeptus Custodes guardian spear; on newer models of the Grey Knights the bolter is a wrist-mounted storm bolter, incorporated into the armour itself.

Sources

• Codex: Daemonhunters
• Warhammer 40,000: Compilation, Grey Knight Terminator Squads

See also

• Force weapons
• Guardian Spear