The Hard Light Sword is a two-handed melee/rangedweapon. The secondary ability, Hard Light Gun, inflicts marks onto enemies, allowing the primary ability to deal critical damage to that enemy, which increases the more marks are applied.
"Applies 2 stacks of damage over time effects instead of 1."
Location
Drops in a loreroom with a monolith that can randomly be found in the Prisoners' Quarters. Examining the monolith will drop the Hard Light Sword. Picking it up will unlock it permanently.
"I feel uneasy when I'm next to this... monolith."
"I should leave fast!"
Notes
Although this weapon has ammo, the projectiles do not stay stuck in enemies so it can't trigger mutations like Ripper and Barbed Tips.
The gun is very weak on its own, relies on melee attacks to replenish ammo and is mainly useful for enabling critical hits for the sword, thus it is recommended to use a brutality build for this weapon.
The gun displays a critical DPS, and is capable of rolling crit-related Affixes, but cannot actually inflict critical hits.
Any pierce-related Affixes greatly benefit the gun, allowing it to apply gun marks to multiple enemies per shot.
Trivia
This weapon and its mechanics, are a reference to the game Hyper Light Drifter.