Colossal Weapons in Elden Ring: Nightreign are the heaviest armaments in the game, delivering the highest poise damage and stagger potential. While, these weapons are incredibly slow and consume a lot of stamina, they are bolstering devastating damage and staggering capabilities with the right loadout and build.
NightreignColossal Weapons - Nightreign Wiki

Axe Of Godfrey
Colossal Weapon • Lvl Required 10
Weapon Skill: Regal Roar
Let loose a mighty war cry, raising attack power, while sending out a shockwave that cannot be guarded against by stomping the ground. While active, strong attack becomes a lunging slash.
Unique Weapon Passive: Power of the First Lord
Weapon of Godfrey, Elden Lord. It was broken in a battle fought as leader of the Tarnished during the Long March. This weapon is symbolic of Godfrey's vow to conduct himself as a lord, later becoming an emblem of the golden lineage. In the days of the past, a crown was warranted with strength.

Dragon Greatclaw
Colossal Weapon • Lvl Required 7
Weapon Skill: Endure
Assume an anchored stance to brace for incoming attacks, briefly boosting poise. Damage taken while using this skill is reduced.
Weapon said to have been whittled from the claw of a great, ancient dragon, wielded by grotesque Tree Sentinels who yet serve the Erdtree. The claw is enwreathed with lightning, and tears through the dragons' feeble descendants with ease.

Duelist Greataxe
Colossal Weapon • Lvl Required 1
Weapon Skill: Endure
Assume an anchored stance to brace for incoming attacks, briefly boosting poise. Damage taken while using this skill is reduced.
Greataxe designed for gladiatorial combat. Used by duelists who were exiled from the colosseum. A weapon reserved for duelist champions, the charge attack is particularly ferocious.

Envoy's Greathorn
Colossal Weapon • Lvl Required 7
Weapon Skill: Great Oracular Bubble
Blow on the horn to release a massive magic bubble. The bubble floats gently through the air towards its target.
Fanned golden horn of the Oracle Envoys. Profoundly weighty, its blows are sure to be felt. Originally an instrument, but one that cannot be sounded by a mere human. Or perhaps it is too early to sound the call.

Fallingstar Beast Jaw
Colossal Weapon • Lvl Required 7
Weapon Skill: Gravity Bolt
Imbue the jaw of fallingstar beast with gravitational lightning, sending a bolt crashing down a short distance away. Can be fired in rapid succession.
Part of a Falling star Beast's jaw, hard and shining black, fashioned into a weapon. With its sharp point, this colossal weapon can skewer foes.

Ghiza's Wheel
Colossal Weapon • Lvl Required 7
Weapon Skill: Spinning Wheel
Strike the wheel against the ground to set it spinning at top speed. Hold to keep the wheel spinning. Can be used while walking to push the armament into enemies.
Great iron wheel lined with flesh-flaying blades. Device of torture used by Inquisitor Ghiza. As the wheel spins it causes severe pain and blood loss. The design was adopted for use as the iconic weapon wielded by Iron Virgins.

Giant-crusher
Colossal Weapon • Lvl Required 3
Weapon Skill: Endure
Assume an anchored stance to brace for incoming attacks, briefly boosting poise. Damage taken while using this skill is reduced.
A hammer made from a boulder, used in the War against the Giants. One of the heftiest weapons in the entire Lands Between. After the giants were quelled, and man turned against man in violence, this weapon was all but forgotten. Man has grown feeble in comparison to his forebears.

Golem's Halberd
Colossal Weapon • Lvl Required 3
Weapon Skill: Charge Forth
Quickly charge forward with the armament at the hip, carrying the momentum into a thrust. Hold to cover a greater distance.
A great halberd of black stone crafted by a civilization now gone to ruin. Wielded by the Guardian Golem.

Great Club
Colossal Weapon • Lvl Required 3
Weapon Skill: Golden Land
Thrust armament into the ground, then gather strength to unleash a blast of sacred energy that coalesces into golden darts. Follow up with a strong attack to swing the armament in a sweeping strike.
An enormous club of hardwood. Wildly hammering foes with this striking weapon requires no dexterity; only brute force. While it may seem sacrilegious, this weapon is said to be a withered branch of the Erdtree. Imbued with holy power, this weapon will never snap.

Prelate's Inferno Crozier
Colossal Weapon • Lvl Required 7
Weapon Skill: Prelate's Charge
Slam armament into the ground to create a surge of flames, then charge in. Hold to continue the charge.
Colossal hammer with the appearance of roiling flames. Weapon of the Prelates who lead the Fire Monks. Its heft represents the weight of their guardianship. The hammer's head is unusually substantial, and strong attacks' will fling foes into the air.

Raider's Greataxe
Colossal Weapon • Lvl Required 1
Weapon Skill: Endure
Assume an anchored stance to brace for incoming attacks, briefly boosting poise. Damage taken while using this skill is reduced.
The Raider's preferred weapon, a greataxe fashioned from a ship's figurehead. On his first voyage, the Raider vanquished countless pirates on the high seas. When a figurehead was dislodged from its ship during a tumultuos back-and-forth, the Raider claimed it for himself, that it might later server as a reminder of his glorious exploits.

Rotten Greataxe
Colossal Weapon • Lvl Required 3
Weapon Skill: Endure
Assume an anchored stance to brace for incoming attacks, briefly boosting poise. Damage taken while using this skill is reduced.
Greataxe designed for gladiatorial combat, now festering with scarlet rot. Used by duelists who were exiled from the colosseum.