From 1d4chan

Somewhat of a oddity even for the Necrons.

A Voidblade is a form of Necron melee weapon, whose gleaming black edge flickers in and out of existence, causing molecular bonds to sever in any foe unfortunate enough to be struck and potentially causing a chain reaction of atomic disintegration.

A Voidblade is capable of piercing any form of infantry armor when this occurs, and its strike has a similar effect to the entropic bite of a Canoptek Scarab upon infantry and vehicle armor. Voidblades are weapons found almost exclusively as part of the armories of Necron royals like Necron Overlords, Necron Lords and Necron Destroyer Lords. However, Triarch Praetorians also often pair a Voidblade with a Particle Caster as an alternative armament to their usual two-handed Rod of Covenant, whilst Canoptek Acanthrites have Voidblades as tail-mounted close combat weapons.

Weapons of the Necrons
Ballistics: Tachyon Arrow
Directed-Energy: Enmitic Disintegrator Pistol - Particle Caster - Scouring Eye
Dimensional: Transdimensional Beamer
Basic Weapons:
Directed-Energy: Gauss Flayer - Gauss Reaper - Tesla Carbine
Special Weapons:
Incendiary: Gauntlet of Fire
Other: Synaptic Disintegrator
Heavy Weapons:
Directed-Energy: Gauss Blaster - Gauss Cannon - Gauss Destructor - Heavy Gauss Cannon
Particle Beamer - Enmitic Annihilator - Enmitic Exterminator
Staff Weapons:
Directed-Energy: Eldritch Lance - Entropic Lance - Rod of Covenant
Staff of Light - Staff of the Destroyer - Voltaic Staff
Other: Abyssal Staff - Aeonstave - Empathic Obliterator
Staff of Tomorrow - Tremorstave
Vehicle Weapons:
Directed-Energy: Death Ray - Focused Death Ray - Gauss Exterminator - Gauss Flux Arc
Heat Cannon - Heat Ray - Particle Shredder - Tesla Cannon
Tesseract Singularity Chamber - Thermal Cutting Beam
Dimensional: Exile Cannon
Superheavy Weapons:
Directed-Energy: Annihilator Beam - Doomsday Cannon - Doomsday Blaster - Gauss Annihilator
Gauss Obliterator - Particle Whip - Tesla Destructor - Tesla Sphere - Æonic Orb
Gravitational: Singularity Generator
Dimensional: Transdimensional Projector - Transdimensional Abductor
Other: Synaptic Obliterator - Atomiser Beam Lance
Ship Weapons:
Directed-Energy: Lightning Arc - Particle Whip Launcher
Non-Firearm Weapons:
Melee Weapons: C'tan Phase Weapons - Hyperphase Weapons - Miscellaneous Weapons - Voidblade
Grenades & Explosives: Countertemporal Nanomine - Death Spheres