Similar to the effects of Vow of Silence from Dark Souls, when cast, causes a wave of dark energy to emit from the player. Any enemy that comes into contact with the wave is unable to cast spells for 30 seconds. However, it does possess a somewhat slow casting time (though not the longest) and players will most likely avoid the caster mistaking it for other spells. Finding an opportune moment to cast is definitely recommended.
- Profound Still has no height limit to its casts, meaning that an enemy can be an entire level above the caster and still be affected.
- It works against the Looking Glass Knight, Prowling Magus and Congregation and the Darklurker. Any NPC invader will also be denied its use of magic, meaning that the fight with Licia of Lindeldt (when the player invades with Crushed Eye Orb) will be significantly easier, as she will only pursue the player to hit them with her chime for the duration of the spell.
- The effect of Profound Still can be avoided by wearing a Sanctum Priestess Tiara.
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