Underworld Fanfiction Crossover Novels & Stories

I was the "Sickly Prince"—a weak scholar hidden in oversized suits. But in the underworld, secrets are the only currency that matters, and mine is the most lethal of all. Aradaa Vaelis has spent twenty-one years hiding his elite combat training from his tyrannical father, the Don. But when his father gambles away his sister’s life, Aradaa is forced to shatter his facade. To save his sister, Aradaa makes a deal with the devil: he will become a human sacrifice for the Dreadfang Clan, a savage "Beast" Mafia known for their monstrous strength. His buyer? Kaelor Dreadfang. Known as the "Beast King," Kaelor is a man losing his mind to a feral rage and a slow poison. He doesn't want a soldier; he wants a "pretty toy" to break. But the moment they touch, a primal Mate Bond ignites—a shockwave of desire that neither can fight. Now, Aradaa is trapped in the King's Master Suite, serving as Kaelor’s "Exclusive." But as the Syndicate moves to destroy them both, Aradaa’s true lineage begins to surface. He isn't just a slave or a scholar—he is the Pure-Blood, the only one capable of curing the bio-weapon plague and ruling the underworld. The "Pretty Prince" is dead. The King’s partner has arrived. And together, they will burn the Syndicate to the ground.

Long ago Legends made flesh collided with the underworld as Dragons and werewolves went to war. In a battle that still rages today, the land was split and dragons took over the business world while werewolves controlled the underbelly and, as the years blended together two names emerged at the top of the shifter foodchain. Ragnar Dalgaard is the last of the pureblood dragonlords. In the business world, his company reigns supreme as it gobbles up the struggling businesses of lesser dragons. Hiding in plain sight amongst the humans, learning from their technology, and adapting their own, Dalgaard Industries is on the cusp of something big. Meanwhile deep in the crime world, Giovanni Lupo is the boogeyman amongst his peers. Sexy and ruthless, Gio and his cutthroat pack rule their world with an iron fist, but the werewolf wants more than slums and backstreets, he wants it all, and no one, neither beast nor human will stop him from getting it. When Charlotte Ren, a beautiful and highly intelligent scientist finds herself lost in the City, a chance encounter with the boogeyman and a job offer from a handsome stranger sets her on a path where old friends and sworn enemies come together in a supernatural clash of the titans, for the chance to win the heart of a human. But is Charlotte willing to let herself be the prize, and who says she has to choose just one of the men fighting for her favor?

Two mafia families. One bloody feud. And a love that was never supposed to exist. Valenti Moretti is known as Ghost—a shadow in the underworld, a man feared for his precision and ruthlessness. But beneath the cold exterior lies a burning obsession he can't escape: Lorenzo De Luca, the golden prince of their rival family. Lorenzo's every smile, every calculated move with his perfect fiancée, is a reminder of what Ghost can never have—or forget. Their story began years ago, with a kiss neither of them were supposed to remember. Now, Ghost has a plan to make Lorenzo face the truth they both buried: a staged kidnapping, a forced reunion, and a chance to rewrite their fate. But Ghost goes a step further, paying the kidnappers to make them sleep together. But love born in the dark doesn’t thrive without consequences. As secrets unravel and both families spiral into chaos, Ghost and Lorenzo find themselves drawn together by the very forces tearing them apart. Loyalties will shatter. Blood will spill. And when the truth about their past comes to light, they’ll have to decide whether their connection is worth destroying everything—or if it was doomed from the start. In this deadly game of power, hate, and obsession, how far will you go to claim the one thing you can’t have?

He was raised by blood and fire. She was born from loss and buried memories. Lorenzo is a ruthless mafia king—cold, calculating, and feared across Chicago and New York. Groomed to inherit an empire soaked in violence, he has spent his life clawing his way toward one goal: freedom. Three more years, and he plans to walk away from the underworld forever, leaving the bloodstained crown behind. But fate has other plans. Mel lives a quiet life defined by art, guilt, and responsibility. Haunted by dreams of a boy with mismatched eyes and surrounded by roses, she believes they are nothing more than fragments of her imagination—until those dreams begin to feel dangerously real. When their worlds collide, buried truths resurface. The boy Lorenzo once was. The girl he once saved. A promise neither of them remembers making—but never truly broke. As enemies close in and the past claws its way back to the surface, Lorenzo must choose between the empire he was born to rule and the woman who could destroy it. Loving her means risking everything—his power, his future, and the carefully controlled monster he’s become. Because some roses don’t bloom to be protected. They bloom to bring kings to their knees. And in a world of thorns, love may be the deadliest weapon of all.

My marriage to Dante Moretti shocked everyone. I’ve got a fiery temper and I don’t back down. Three years into our marriage, the entire Chicago underworld knew we were at each other's throats. Except in bed. There, our bodies just fit. The only time we weren't at war was when we were tangled in the sheets, lost in a storm of desperate kisses and raw pleasure. Countless times, he’d tell me he was obsessed with my body, always right as he was sinking into me. I thought it was his way of saying he was falling for me. That all came crashing down at an auction, when he snatched my mother's heirloom from me, only to give it to her—a fragile-looking girl named Ava. That’s when he showed me a cruelty I’d never seen. "It's time for a reality check, Elara," he’d said, his voice cold as ice. "Marrying you, fucking you… it was all just to keep the peace between our families. Ava is the one I want to protect." But the day I finally left Chicago, the day I announced our divorce to the world… That cold, calculating Mafia Don hunted for me like a man possessed.

Running from hell, and towards the devil. Having caught her betrothed and her stepmother in an unforgivable act, Calista runs away into the arms of a stranger-Roman Cappellucci, the cold, calculating, and dangerous mafia boss of Chicago. Roman has worked his way to the top of the criminal underworld with brutality. He proposes a deal: marry him, and he'll protect her. No feelings. No questions. Just safety in exchange for her obedience. But safety has its price It's supposed to be simple, a marriage of convenience for her protection. And don't they say the devil you know is better than the angel you don't know? Things take a twisted, darker turn when Roman's truest nature begins to unfold. He is not the savior she thinks he is; he is the devil that would set the world ablaze for her sake. The abyss she wants to drown in even though he is ruthless and emotionless. Yet with every passing day, Calista begins to chip away at the ice around Romano's heart. And despite every warning in her head, she finds herself drawn to him—not out of fear, but fascination. Her protector Her obsession Her every, darkest fantasy. Because the devil didn’t just save her. He claimed her.

I woke up, and I was 28 again. I had twin heirs, and my husband was Santino, Veridia's most feared Mafia Don. He sat at the head of the Commission of the Five Families. His sharp profile was a fixture on the cover of the underworld's most exclusive magazine for several consecutive issues. Even the oldest Valerian families were lining up to offer him their daughters. All the women in Altoria envied my good fortune. But the first thing I did after waking up was pick up the divorce papers, the ink still fresh, and handed them to his childhood sweetheart, Jessy. "My lawyer will handle the divorce. The properties and assets are yours. Santino is yours. The children are yours, too." Sitting across from me, Jessy couldn't believe it, her eyes wide with shock. "Are you crazy, Alessia? Is this some kind of trick?" "How could the woman who has been Donna for six years give it all up so easily?" I lowered my gaze, my tone calm. "Since they all prefer you, I figured it was time to step aside." "Just have Santino sign it and press his signet ring into the wax seal." "Once the divorce is final, I'll leave Veridia for good." This time, I would not make the same mistake. I would never again be a Donna in name only.

"I, Alpha Dante Moretti, don't want your money. I want your name. And I want you." Julian Vane was the "Golden Prince" of the city until his family's empire was burned to the ground. In a single night, he went from a King to a prisoner, sold by his own brothers to settle a blood debt with their greatest enemy: Dante "The Butcher" Moretti. Dante is cold, ruthless, and obsessed with control. He forces Julian into a "Blood Marriage, a vow that makes Julian his property. The plan was simple: break the Prince, take the Vane family secrets, and discard the remains. But Julian is no longer the pampered heir they remember. Betrayed by his blood and caged by a monster, Julian discovers a darkness within himself that matches Dante’s own. As the line between hate and obsession blurs, the "Golden Prince" must decide if he will kill the man who owns him, or rule the underworld by his side. In a world of silver-plated guns and red-stained silk, Julian will learn that silence is a weapon, and Dante will realize that he didn't just buy a husband, he invited a predator into his bed. "You can own my body, Dante. But if you touch my soul, I’ll make sure yours is the first one I send to hell."

Four years of marriage. One signature—his own—that set me free, though he never realized what he was signing. I was Sophia Moretti, the invisible wife of James Moretti, heir to the city’s most powerful mafia family. But when his childhood sweetheart, the dazzling and privileged Vicky, returned, I finally understood: I had always been temporary. So I played my final move. I slid the papers across his desk—divorce disguised as routine university forms. James signed without a second glance, his fountain pen scratching across the page as carelessly as he'd treated our vows, without noticing he was ending our marriage. But I walked away with more than my freedom. Beneath my coat, I carried his unborn heir—a secret that could destroy him when he finally realized what he'd lost. Now, the man who never noticed me is tearing the world apart trying to find me. From his penthouse to the underworld's gutters, he's turning over every stone. But I'm not some trembling prey waiting to be found. I rebuilt myself beyond his reach—where not even a Moretti can follow. This time, I won't be begging for his love. He'll be begging for mine.

In a city where the Morano family's grip on power is suffocating, loyalty is a luxury that few can afford. For Alex Morano, the youngest son of the family, the weight of his family's legacy is crushing. When a prominent businessman is murdered, Alex is accused of the crime and must navigate the treacherous world of organized crime to clear his name. The Russos, a rival mafia family, are seeking to take down the Moranos and claim the city's underworld for themselves. But as Alex digs deeper into the mystery, he uncovers a web of deceit and corruption that threatens to destroy everything he holds dear, and Alex's own family is hiding secrets that could destroy them all. As Alex's world implodes, he finds himself torn between his loyalty to his family and his growing feelings for Sophia, a mysterious woman with ties to the mafia world. But Sophia's true intentions are shrouded in mystery, and Alex must confront the possibility that she may be his greatest enemy. “The Mafia’s Reckoning” has gritty realism, complex characters, and heart-pumping action, "The Mafia's Reckoning" is a gripping tale of loyalty, power, and survival. As Alex navigates the dark and treacherous world of organized crime, he must confront the ultimate question: what does it mean to be loyal to oneself and one's family in a world where loyalty is a luxury that a few can afford?