In Elden Ring: Nightreign Ashes of War are powerful weapon skills that can unleash devastating damage or provide additional utility. Depending on the weapon skill found on the weapon itself, it can change damage profile and status ailment buildup of a weapon. They can be randomly obtained in the world of Limveld. Some Ashes of War are unqiue in nature and can only be found on certain unqiue weapons.
NightreignAshes of War (Weapon Skills) - Nightreign Wiki

Alabaster Lord's Pull
Ash of War
Thrust the armament into the ground to create a gravity well. In addition to dealing damage, this attack pulls enemies in. Has a greater area of effect than Gravitas.
Usable with specific armaments

Ancient Lightning Spear
Ash of War
Imbue the armament with the ancient dragons' red lightning, then throw it as a spear. Can be charged to increase its power.
Usable with specific armaments

Angel's Wings
Ash of War
Jump and imbue the wing-blade of the armament with light, then deliver a slashing attack on the enemy. The white wings impede recovery actions using a flask of tears.
Usable with specific armaments

Assassin's Gambit
Ash of War
Skill that masks the user's presence at the cost of a self-inflicted wound. Grants near-invisibility and silences footsteps.
Usable with small and medium straight swords and thrusting swords

Barbaric Roar
Ash of War
Let loose a bestial roar to rally the spirit and increase attack power. While active, strong attacks change to savage combo attacks
Usable with melee armaments (excluding daggers, thrusting swords, and whips)

Barrage
Ash of War
Archery Skill using a bow held horizontally. Ready the bow, then fire off a rapid succession of shots faster than the eye can see.
Usable with bows

Barricade Shield
Ash of War
Skill made famous by Sir Neidhart. Focus your energy into the shield, temporarily hardening it to deflect greater blows.
Usable with all shields

Bear Witness
Ash of War
Grant the small dragon a fleeting glimpse of life and thrust it skyward, spewing flames over a wide frontward area.
Usable with specific armaments

Beast's Roar
Ash of War
Unleash a beastly roar, rending the air as a forward-traveling projectile.
Usable with all melee armaments

Black Flame Tornado
Ash of War
Spin armament overhead and then plunge it into the ground to summon a raging vortex of black flames. Hold to create an initial flame tornado while spinning the armament.
Usable with polearms and twinblades

Blade Of Death
Ash of War
Unleash the power of the Rune of Death to fire off a blade-like projectile. In addition to dealing immediate damage, the blade reduces the enemy's maximum HP and continues to wear down HP for a while.
Usable with specific armaments

Blade Of Gold
Ash of War
Leap into the air, charging the armament with golden flames that are then shot at the enemy as a single, blade-like projectile. Inflicts holy damage.
Usable with specific armaments

Blood Blade
Ash of War
Wound self to coat the armament with blood, then unleash an airborne blood blade that causes hemorrhaging. Can be fired in rapid succession.
Usable with small and medium swords

Bloodblade Dance
Ash of War
Leap at foe to perform a flurry of tornado-like attacks. Follow up with an additional input to perform an attack that ends in an evasive maneuver.
Usable with specific armaments

Bloodboon Ritual
Ash of War
Raise the sacred spear and pierce the body of the Formless Mother. Stab up to three times, creating explosions of blood with each thrust. This skill will coat the armament with bloodflame for a while.
Usable with specific armaments

Bloodhound's Finesse
Ash of War
Slash upwards with the Bloodhound's Fang, using the momentum of the strike to perform a backwards somersault and gain some distance from foes. Follow up with a strong attack to perform the Bloodhound's Step attack.
Usable with specific armaments

Bloodhound's Step
Ash of War
Skill that allows the user to become temporarily invisible while dodging at high speed. Moves faster and travels farther than a regular quickstep. This skill can be used to circle around lock-on targets.
Usable with all melee armaments

Blood Tax
Ash of War
Blood Oath skill granted by the Lord of Blood. Twist to build power, then unleash a flurry of thrusts that rob the target of both their blood and their HP.
Usable with armaments capable of thrusting (excluding colossal weapons)

Bloody Slash
Ash of War
Blood Oath skill granted by the Lord of Blood. From a low stance, coat the blade in your own blood to unleash a rending blood slash in a wide arc.
Usable with swords (excluding colossal weapons)

Braggart's Roar
Ash of War
Declare your presence with a boastful roar. Raises attack power, defense and stamina recover speed.
Usable with melee armaments (excluding daggers, thrusting swords, and whips)

Bubble Shower
Ash of War
Blow on the horn to release a spume of magic bubbles. The bubbles float gently before raining down on the target.
Usable with specific armaments

Buckler Parry
Ash of War
Use this skill in time with a foe's melee attack to deflect it and break that foe's stance. This is faster than a regular parry.
Usable with small shields

Carian Grandeur
Ash of War
Carian royal prestige embodied in a skill. Transform blade into magical greatsword and swing it down. Can be charged to increase its power by up to two levels.
Usable with swords (excluding colossal weapons)

Carian Greatsword
Ash of War
Carian royal prestige embodied in a skill. Transform blade into a magical greatsword and swing it down. Can be charged to increase its power.
Usable with swords (excluding colossal weapons)

Carian Retaliation
Ash of War
Swing the shield to dispel incoming sorceries and incantations, transforming the magic into retaliatory glintblades. Can also be used in the same way as a regular parry.
Usable with small and medium shields

Charge Forth
Ash of War
Quickly charge forward with the armament at the hip, carrying the momentum into a thrust. Hold to cover a greater distance.
Usable with polearms capable of thrusting, heavy thrusting swords, and twinblades

Chilling Mist
Ash of War
Coat armament in frost, and then slash, spreading frigid mist forwards. The armament retains its frost for a while.
Usable with melee armaments (excluding whips, fists, and claws)

Claw Flick
Ash of War
Cause the finger to swell, then flex to build up strength before giving enemies an almighty flick.
Usable with specific armaments

Contagious Fury
Ash of War
Incite the jellyfish's wrath and allow its fury to flow through you. Raises attack power for a certain duration.
Usable with specific armaments

Corpse Piler
Ash of War
Forms a blade of cursed blood for repeated, interweaving successive attacks. Follow up with an additional input for further successive attacks.
Usable with specific armaments

Corpse Wax Cutter
Ash of War
Lost skill of ancient heroes. Lift the sword up high to release the power of corpse wax and launch it forwards as a blade-like projectile.
Usable with specific armaments

Cragblade
Ash of War
Skill that manipulates gravity. Bury the armament in the ground, pulling rocks from the earth to reinforce it. Increases attack power and makes it easier to break enemy stance.
Usable with melee armaments (excluding whips)

Cursed-blood Slice
Ash of War
Brace, then charge forward to deliver a downward diagonal slice. The bloody trail of the late is followed by a burst of flame. Additional input allows for a follow-up attack.
Usable with specific armaments

Death Flare
Ash of War
Set the lusterless sun ablaze with the Prince of Death's flames, inflicting the death ailment upon foes. Follow up with an additional input to bring down the armament, triggering an explosion.
Usable with specific armaments

Destined Death
Ash of War
Set free the remnants of Destined Death, plunging the greatsword into the ground to summon a myriad of blades. In addition to dealing immediate damage, this attack reduces the enemy's maximum HP and continues to wear down HP for a short time.
Usable with specific armaments

Determination
Ash of War
A knightly skill. Hold the flat of the armament to your face and pledge your resolve, powering up your next attack.
Usable with all melee armaments

Devourer Of Worlds
Ash of War
Charge the scepter with magic and strike it against the ground to steal the HP of all nearby enemies.
Usable with specific armaments

Double Slash
Ash of War
Skills of superior swordsmen. Perform a crossing slash attack from a low stance. Repeated inputs allow for up to two follow-up attacks.
Usable with swords and polearms capable of slashing (excluding colossal weapons)

Dynast's Finesse
Ash of War
Nimbly avoid an attack, securing some distance from foes. Follow up with strong attack to perform a sudden lunge, and press strong attack again to perform a sweeping slice.
Usable with specific armaments

Earthshaker
Ash of War
Thrust armament into the ground, then gather strength to unleash an earth-shaking shockwave. Follow up with a strong attack to swing the armament in a sweeping strike.
Usable with greataxes, great hammers, great spears, and colossal weapons

Enchanted Shot
Ash of War
Archery skill that enlivens the arrow with spiritual essence. The resulting shot will fly faster than regular shots and change its trajectory to follow the target.
Usable with bows

Endure
Ash of War
Assume an anchored stance to brace for incoming attacks, briefly boosting poise. Damage taken while using this skill is reduced.
Usable with all melee armaments

Eochaid's Dancing Blade
Ash of War
Infuse the sword with energy, then fling it forwards in a corkscrew attack. The sword continuously deals damage while violently spinning. Charge the attack to increase reach and duration of the spin.
Usable with specific armaments

Erdtree Slam
Ash of War
Jump high up into the air and crash down on the ground ahead. The resulting pratfall sends golden shockwaves in all directions. This is the most powerful of all the Ground Slam skills.
Usable with specific armaments

Eruption
Ash of War
Skill of the knights who serve at Volcano Manor. Slam armament into the ground, spawning roiling lava which spouts up upon release.
Usable with large and colossal swords, axes, and hammers

Establish Order
Ash of War
Raise the armament in a salute, releasing a golden explosion. Repeated inputs send out waves of golden light.
Usable with specific armaments

Familial Rancor
Ash of War
Gently rattle the copper heads to summon vengeful spirits that chase down foes. The anguish of a spouse and children invites accursed wrath.
Usable with specific armaments

Firebreather
Ash of War
Blow into torch flame, spreading flames in a wide frontward arc. The flames on the ground will continue to burn for a short time.
Usable with specific armaments