Underworld Fanfiction Crossover

As a child, Elena Carter witnessed the brutal murder of her father, a decorated detective, at the hands of men she believed to be part of the Mafia. That night, her world shattered, and she vowed to dedicate her life to avenging his death. Years later, she becomes a detective, determined to bring down the very criminal empire she holds responsible. Her mission leads her deep into the city’s underworld, where she goes undercover to get close to the ruthless and enigmatic Adrian Moretti, a powerful Mafia boss feared by many. Cold, calculated, and untouchable, Adrian is a man who trusts no one—but when he crosses paths with Elena, something shifts. She intrigues him. She challenges him. And, against all logic, he lets her in. As Elena gets closer to him, her resolve wavers. The man she was sent to destroy is not the monster she expected. But the deeper she falls, the more dangerous her web of lies becomes. And when the truth is revealed—that Elena is not only a cop but the daughter of the detective who was killed that night—Adrian’s world comes crashing down. But the truth runs even deeper than Elena ever imagined. The police force she serves is not as righteous as she believed. Her own agency orchestrated her father’s murder, framing the Mafia to cover up their own corruption. Now, the people she trusted want her dead, and the only person who might be able to protect her… is the man she betrayed. With enemies closing in from all sides, will Elena and Adrian fight for love, or will the past destroy them both?

He leaned in, inhaling her sweet scent as his hands traveled from her back to her waist, and then down to her thigh. She felt her breath hitch as she let out a small gasp. "We shouldn't be doing this." She said, her voice barely above a whisper. "Then tell me to stop." His voice was low, daring, as his fingers traced slow circles on her skin. *** Lucy had always lived life on her own terms, until the night everything changed. One moment, she was free; the next, she was bound to Barry Cooper, a cold, dangerous man who ruled the underworld with an iron fist. She never expected to be trapped in a world of power struggles, deceit, and unspoken desires. But as the lines between captor and captive blur, Lucy realizes she’s caught in a deadly game, one where trust is a luxury and survival is not guaranteed. Will she escape the ruthless mobster who owns her… or will she become his greatest obsession?

Two alpha males. One forbidden siren. A bond that breaks every rule. Althea Lake has always known she was dangerous. As a siren, her beauty and voice were crafted by nature to lure powerful mates—and in a world ruled by dominance and legacy, sirens are both coveted and feared. Desired by kings, claimed by titans, and whispered about in secret, they are walking temptation. But Althea isn’t hunting for power. She’s hiding from it. That is, until fate brings her face-to-face with the two most dangerous—and unclaimed—males in the supernatural world. Cassian Morningstar, the Demon King of the underworld and a cold-blooded CEO by day, built his empire with ruthless control. Xanden Moon, a deadly fae warrior and Cassian’s co-ruler, is known for his loyalty, precision, and barely leashed violence. Neither has ever found their fated mate. Until her. Althea is theirs. The bond is undeniable. But a siren having two mates? Unheard of. Forbidden. And potentially catastrophic for the balance of power in their world. Torn between her fear of being claimed and the impossible heat pulling them together, Althea must decide whether to resist her nature—or surrender to a destiny that could consume them all. In a world of magic, power, and primal instincts… some rules were made to be broken.

In Valeburn, Atlanta’s most dangerous block, power doesn’t pass hands—it’s taken with blood. And no one understands that more than Jayce Navarro, the razor-sharp kingpin who built his empire brick by brick, silence by silence. He rules with cold precision, a name whispered like a gun being cocked—until the ghost of his past returns with vengeance on his breath. Eli Mercer is no longer the soft-eyed teen Jayce once kissed beneath the chapel steps. Fresh from the feds and wrapped in scars, Eli returns to the block with one purpose: burn down the throne that forgot him. But when fate—and the city’s shifting underworld—forces them into an uneasy alliance, old feelings smolder beneath their armor. Lust tangles with rage. Loyalty with betrayal. And love? It’s the most dangerous weapon of all. As enemies circle from the inside and the state threatens to dismantle Jayce’s entire operation, he and Eli must decide what’s worth saving—their empires, their reputations… or each other. But in Valeburn, every crown is cursed. And every favor comes with fire.

She sold her soul to save her daughter… but the devil wears a billionaire’s smile. Emily Carter is a desperate mother clawing her way through the filth of New York’s underworld, dancing for dollars in a club that devours women whole. When her baby girl falls deathly ill, she’s forced into an impossible choice: let her child die… or marry a cold-hearted billionaire with a past darker than her own. Alexander Richie doesn’t believe in love but he believes in ownership. His proposal isn’t a lifeline. It’s a leash. Thrust into a mansion of lies, judgment, and cruel stepchildren, Emily trades one nightmare for another. Her new life is gilded in luxury but soaked in venom, and the people inside want to break her. But Emily didn’t survive the streets to become anyone’s victim not even his. Love wasn’t part of the deal. But what happens when the broken start to feel? And how many bodies must fall before the truth is revealed?

“Marry me Giselle.” He breathes into my neck. “I can't, you belong to another Romero.” I whisper. Giselle Gilmore, a girl whose past has been turned upside down in a life of crime and violence gets involved with Romero De La Rosa, the most feared and powerful Mafia Lord and becomes too attached to his daughter Lauryn De La Rosa. When she gets a chance to reunite with the family, a long time family alliance made with another Mafia family engaging Romero De La Rosa to another woman in marriage appears and any bridge of the arrangement will lead to the biggest war ever witnessed in the underworld. Will Romero De La Rosa bend backwards to the underworld rule or will he fight for his love.

By day, Carlotta spins stories. By night, she serves drinks. Her life was simple. Until her good-for-nothing brother offered her as collateral to pay off a massive gambling debt to a ruthless underground casino. Now she's the reluctant fiancée of a powerful mafioso rumored to have a cruel streak... and a bedroom secret that's the talk of the criminal underworld: erectile dysfunction. Carlotta would've found it funny if it weren't her life on the line. To make things worse, fate throws in another complication: her dangerously attractive new driver-slash-bodyguard. With abs worthy of a thirst trap and a face that screams "Asgardian demigod". He's the kind of temptation a woman in her situation absolutely does not need. Just when she thinks it couldn't get more absurd, her cold, mysterious fiancé summons her to his penthouse suite with one chilling demand: He wants a taste of what's been promised. Her.

She was set up for murder, betrayed by her ex and her best friend... Framed, broken, and left to rot in a hospital bed. Sally had no one left… Except him. Dante 'Doom' Castillo. He was feared by the underworld, worshipped by the mafia, he was her father’s brother, her forbidden obsession. The one man who swore to protect her but not out of love, he wanted something she never even knew she had. A key. To a secret so dangerous, it shattered everything she thought she knew about her life. The fake murder, the betrayal, the inheritance, and the seduction was all a carefully orchestrated game designed to make her run straight into his arms and she did but Sally was done being played, because now she knows what he’s hiding. What he became the moment she shattered the one thing he needed most... Now he’s unstoppable and unkillable. And the worst part? She still wants him.

Milo Petrov ruled Russia’s underworld with an iron fist. For years, I was nothing more than his possession—his plaything, his captive. His wealth and dangerous charm ensnared me, but I couldn’t escape the truth: I was nothing more than a pawn in his game. At just 19 years old, I never imagined my life would spiral so far out of control. He was ruthless, but everything about him intrigued me. The only problem? I had once loved his son, Andrew. Now I found myself torn between the deadly allure of Milo and the guilt of betraying Andrew, my first love. Could blood really be thicker than desire? My name is Emilie, and this is the twist story of how Milo Petrov took my heart and shattered my world.

A Dark Mafia Romance , Dual POV , Forced Marriage , Obsession , Betrayal , Secret Identity Leona Moretti thought she was saving her brother’s life when she agreed to marry New York’s most feared mafia boss. She was wrong. Dante Rizzo didn’t take her out of mercy. He took her because she was promised to him. Sold by her own brother like a piece of flesh, packaged with a smile and a wedding ring. And Leona walked willingly into the trap. Now she wears his name. Sleeps in his bed. Lives in a mansion guarded like a prison. But he doesn’t touch her. Not yet. He watches. He waits. He burns. Dante is cold, cruel, and unreadable...until she disobeys him. Until she presses the wrong button. Until the mask cracks and she sees what he really is: A man obsessed. Possessive. Completely unhinged when it comes to her. But Leona has secrets of her own. Like the fact that she may not be a Moretti at all. And her entire life? A carefully constructed lie hiding a truth soaked in blood and betrayal. She’s not just a pawn in a mafia game. She’s a daughter of the deadliest name the underworld ever buried. And Dante? He’s not planning to let her go. Not when he finally has the one thing he's been denied his entire life. Her.