Maybe a Fake Gintama - Chapter 20: The Thing More Hateful Than Not Being Able to Keep the Promise Is Forgetting the Promise! (Otsuu’s Father Part 2)

Synopsis below:How did the Avatar universe change when a transmigrant appeared in an unknown village, long before the canonical events? And how are the two islands Kyoshi Island and Uzushiogakure no Sato (A village hidden in the maelstrom)?---Tags: AU, Before-canon, Post-canon, Violence, Death of major characters, Transmigration, Harem, Children, Incest, Romantic. Foul language.

One god, one faith, one world, one mage… I am the only mage in the world.

- Description from Ptwxz (translated)

Mercy Morgan was just an ordinary young man trying to make sense of his life, but fate had other plans. One fateful night while on the verge of death, he crossed paths with Michelle Elderblood, an ancient vampire whose bite changed everything. Now transformed into Merciless Minerva Elderblood II, he finds himself thrust into a hidden world of powerful vampires and dark secrets.In this realm, where myth collides with reality, Merciless quickly realizes he is caught in a dangerous web of many powerful creatures. Meanwhile, the vampires operate under a singular, formidable king, and every encounter reveals the treacherous politics and hidden agendas that dictate their lives. Yet, amid the chaos, a singular purpose ignites within him: revenge.Merciless barely a day old must face a harrowing exam that plunges him into the depths of forbidden knowledge, forcing him to confront not only the secrets of his new existence but also the gods who have forsaken him. The pain of his past fuels his determination, and as he navigates this perilous path, he wrestles with the question of whether he is merely a pawn in someone else's game before becoming a vampire, or if he is destined for something far greater.Driven by a relentless thirst for vengeance, Merciless must gather strength and confront the darkest parts of his new identity. With every step he takes, the stakes rise, leading him closer to a confrontation that could alter the very fabric of his world.Join Merciless on a gripping journey of discovery, power, and the quest for retribution. In a dark world filled with myth, danger, and relentless ambition, can one man's desire for revenge reshape his destiny, or will it consume him entirely?

I was proposed to by the Final Boss.