Waves of Darkness is a Skill in Elden Ring. Waves of Darkness is a skill that plunges armament into the ground to release three waves of darkness. 

Elden Ring Waves of Darkness Guide, Notes & Tips

• This is an Ash of War Skill, associated with the Ash of War: Waves of Darkness.
• FP Cost: 16
• Heavy Attack follow-up FP Cost: 5
• This Skill is not Chargeable
• Deals 34 stance damage
• Testing across Heavy, Cold, and Magic affinities indicates that although affinity affects base damage for each wave in the ash of war, it has no effect on scaling. Magic affinity increased base skill damage the most, followed by Cold and then Heavy. Scaling appears to be intelligence based with a 5 point increase from 29 to 34 adding approximately .97% damage to each wave regardless of affinity.