Similar to the effects of Dark Weapon, casting Resonant Weapon grants an extra 50 Dark damage to the enchanted weapon. However, like Resonant Flesh, the Dark Bonus boost and duration depend on the amount of souls held at the time of casting. Should the player possess little to no souls when casting the spell, then they will only gain a 10% boost, and the effect will only last for 10 seconds; alternatively, when cast with 2,000 souls, the player gains a boost of 50%, and the spell will last for 60 seconds. Upon casting the hex, 2,000 souls will be consumed. If less than 2,000 souls are in the player's possession, they will all be consumed.
Like all other spells, the amount of casts per slot increases upon reaching certain Attunement milestones:
|Attunement Level||Amount of Casts|
| Affinity • Climax • Dark Dance • Dark Fog • Dark Greatsword • Dark Hail • Dark Orb • Dark Weapon • Darkstorm • Dead Again|
Great Resonant Soul • Lifedrain Patch • Numbness • Profound Still • Promised Walk of Peace • Recollection • Repel
Resonant Flesh • Resonant Soul • Resonant Weapon • Scraps of Life • Twisted Barricade • Whisper of Despair