Nameless King - Chapter 809 Intervention

(Naruto + Single Heroine Tsunade + Romance + Action)A failed author transmigrates into the Naruto world, becoming the younger brother of Konoha’s White Fang, Sakumo Hatake, and the uncle of Kakashi. He gains a cheat ability—enhanced cellular activity.Coincidentally, just before the Second Shinobi War, he participates in a Jonin meeting where he supports Tsunade's proposal ahead of Dan Kato, marking his first encounter with her.From then on, he launches an intense pursuit, winning her heart during the war.Tsunade: “Kawakaze, why do I keep losing to you?”Kawakaze Hatake: “Because I’d like to live a few more years...”Kakashi: “My uncle is amazing, I’m his biggest fan!”Kawakaze Hatake: “Keep it low-key, keep it low-key.”

[Warning! The MC here is the literal incarnation of evil and madness throughout the story.]Valtar Titanblood formerly known as Ethan Martin on Earth was struck by an unimaginable tragedy and took his own life at the end, his whole life filled with misery and incompetence of his own doing.Then he transmigrates to a world of infinite proportions and power that defies logic, this new world which is filled with Dragons, Titans, Ouroboros, and countless more bloodline creatures and mythical beings, also powerful humans who are known as Mystic roams here as well.Valtar in this new world has the Karma System and the bloodline of an unknown titan running through his veins, with these powers in hand he who was supposed to become the symbol of justice and equality decided to become the paragon of madness and evil.He who had the tools to become the Judge of Truth and the figure of Respect chose to become the arbiter of chaos and the embodiment of fear.

Liu Fang, a manager, died suddenly at work due to being too diligent.
She thought that she would turn into a wisp of dust and dissipate after her death, but she never imagined that – the new century, the new underworld, even if she became a soul, she would still be a worker!

Liu Fang has become a newcomer to the underworld Quick transmigration Department. In order to wait for a good reincarnation, she strived to accumulate merit and traveled into one world after another to repair the way of heaven.

- Description from Novelupdates

In novels with a stud there is always a Senior Martial Brother like this:

In the early stages of the novel, his innate talent is high, his cultivation is good, his appearance is handsome, and he has an intelligent, cute younger Martial Sister as a fiancée.

In the middle stages of the novel, he is caught unprepared and defeated by a young disciple (the protagonist) in the sect who’s hardly remarkable at all. From then on, he falls from his godly altar and loses his brilliance. Even his young Martial Sister leaves him for someone else.

In the late stages of the novel, he continues to turn dark, going down the Demonic Path and becoming the major villainous boss. However, the protagonist still ruthlessly defeats him and his soul is eternally sealed.

Once Qin Mo opened his eyes, he discovered that he had become this Senior Martial Brother.

- Description from Novelupdates