Ink and Ember (Sukuna x F. Reader) NSFW

Modern Era, non-canon. Sukuna x Female Reader. Sukuna is head of Drug cartel You're a tattoo artist with a hidden past and your sister is dating his nephew Yuji Itadori.
Better quality image of artwork cover in authors notes. In this story:

In a modern city shadowed by cartel empires and gleaming bioengineering fronts, a deadly synthetic drug called "Curse" ravages the streets, turning users into frenzied, self-annihilating monsters with one fatal dose. Its source is a lethal enigma, and you've been blackmailed into uncovering it, your dark past as a special ops agent and mercenary weaponized against you to protect your younger sister, Isla.

To the world, you're just the vibrant owner of Ink and Ember Tattoo Studio, obsessed with motorcycles, horror flicks, cats, and intricate geometric designs. But when Ryomen Sukuna, the ruthless cartel kingpin behind Curse, storms into your shop with his second-in-command, Toji Fushiguro, to collect his nephew Yuji Itadori and Toji's son Megumi, your worlds collide.

Yuji's budding romance with Isla pulls you into Sukuna's orbit. To you, he's a surly, tattooed enigma with crimson eyes and infuriating charm. Unaware he's the monster you're hunting, your reluctant encounters, awkward pickups, steamy tattoo sessions, chaotic parties, and a dinner that erupts into moonlit beach passion....spark an undeniable fire.

As your investigations edge closer to his empire and he uncovers your "colorful" secrets, desire turns deadly. In this high-stakes tangle of betrayal, violence, and vendettas, will you surrender to the flames... or become the hunter?