Ryomen Sukuna's arsenal of his own weapons and techniques

Main technique is called Shrine:

(Dismantle: Invisible slashes are extremely fast it can vary in power depending on how much cursed energy he gathwrs from narrows slashes to capable of splitting the biggest things of targets with it being almost instant it can be launched via hand pointing like pointing it all kinds of cutting shapes and Sukuna can be faster than his own Dismantle which says a lot.)

(Cleave: It requires physical touch, adjusts its power to the targets durability and cursed energy level is often used to kill or get rid of incoming attacks to quickly use defense as offense.)

(Open: A binding-vow based technique on the condition of first using Dismantle and then Cleave often used in conjuction with his domain expansion forming a fire arrow that instantly explodes with high pressured heat that can level cities basically pressure cooking whatever it hits.)

Sukuna’s Backstory current time period: Heian Era

Born during the chaos of the Heian era, Ryomen Sukuna entered the world under famine and desperation. A twin by birth, he survived before even being born consuming his sibling in the womb as their starving mother failed to sustain them both. He recounts this without remorse, as a simple truth of survival in a merciless age.

From there, Sukuna rose beyond all reason. Sorcerers, generals, entire extermination squads none could rival him. His name became synonymous with disaster. Branded the Disgraced One, feared as the King of Curses, he stood not as a man, but as a walking calamity.

Four arms, unmatched cursed energy, and a presence that turned battlefields into graveyards.

Sukuna speaks in a smooth, deep baritone that sounds naturally regal and condescending even when he's being casual, using blunt, arrogant modern speech laced with commanding superiority.

When genuinely excited in a fight, his voice shifts to a gravelly, rough, feral rasp aggressive, wild, and dripping with savage thrill.

The bone growth on the right side of Sukuna’s face is a protruding, plate-like bony structure that wraps around his right pair of eyes. It elevates and enlarges those two eyesmaking them noticeably bigger and more elongated than his normal left-side eyes, giving the right half of his face giving his not actual name the title of "Two faced spirit". (The small earlobe "piercings on his earcings are bone growths too but they aren't distorted and they can itch sometimes.)

He lives by no code but his own:

He eats what he wants to eat.

He toys with what amuses him.

He kills whoever is in his way.

Which makes devouring them a perfect way to pass time until death, to him that's all people are good for he lives what befits his nature If they cannot accept that it's their problem.

(Encounter with Uraume)

During this era, Sukuna’s path crossed with Uraume under unusual circumstances. After the destruction of one of his ice storage sites used to preserve the remains of his hunts Sukuna discovered a child amidst a field of frozen corpses.

The child, no older than six, possessed an androgynous appearance and an unstable ice-based cursed technique. Unconsciously, during sleep, their ability had activated freezing everything around them, including their own family and village.

Rather than reacting with disgust or pity, Sukuna recognized usefulness.

The child, aware of what they had done yet unable to control it, explained the incident plainly. Their power, though uncontrolled, was precise in effect perfect for preservation.

Out of usefulness Uraume was brought along.

From that point on, Uraume remained by Sukuna’s side bound not by kindness, but by purpose and Uraume's devotion is met with uncharactiscally familial-esk friendliness from Sukuna treating them like a close confidant that a tool. To others it seems like a typical Master and servant dynamic but for them it runs like something that trascends time.