Douluo Dalu 2: The True God King - Chapter 31: [DD2]:

Ye Yang, the son of the Ye Family in Eight Desolate City, was once regarded as a genius. He could awaken his Dantian at the age of three and reach the third level of Qi Condensation at the age of five. But after a few years, He was seen as a person without talent because his cultivation was still stagnant at the age of 16. One day, He was framed and kept in a coma after he was rescued.

Ye Yang was originally an instructor in a special troop. He was 21 years old and sacrificed his life to protect an unknown broken sword which was found on Everest. When he woke up, he became Ye Yang from the Eight Desolate City, unexpectedly obtained the recognition of the broken sword and learned the mysterious cultivation method “God Slaughtering Technique”. He then embarked on a path of cultivating through slaughter.

When he was reborn, he swore, “I won’t let those who offended me off.” He wanted to reach the peak step by step, and also carried the mission to uncover the secret behind the Nine Heavens Mysterious Sword.

- Description from Novelupdates

Dual cultivation isn't a choice; it's a necessity.

After being struck by a truck like most lucky protagonists (or unlucky ones), Vaan found himself transmigrated into the body of an orphan in the world of witches and demons.

However, they didn't always exist.

Demons terrorized the world ever since the Gehenna Realm descended over 300 years ago. but along with them, came mana, giving birth to witches to combat these demons.

Since then, the world of men was dominated by witches, establishing the seven witch kingdoms, which safeguards at the forefront of the demon invasion.

In order to survive in the matriarchal society of the witch kingdoms, Vaan, like all other men who cannot use magic, had to learn how to service the witches to survive.

Nevertheless, it did not come without its own benefits.

Years of research have led the world to the discovery of intimacy between men and women could increase the witches' mana absorption.

But at the same time, men could absorb some of this mana to improve their physique and lifespan.

Thus, since then, an intricate relationship was formed between men and witches in the red-light districts. Love became casual, and dual cultivation is common.

As a prodigy in the art of pleasing women, Vaan lived a smooth two years since his transmigration as an orphan.

However, everything came crashing down in a heartbeat one day when his life was nearly taken, and Lady Eniwse whom he served went berserk.

Even so, that was not the end.

With the awakening of the Witch Hunter System, watch how Vaan takes on the world and becomes the lord of witches.

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Note: Contains lemons.
Hunting witches does not necessarily imply killing witches if you know what I mean ( ͡° ͜ʖ ͡°)

Insane. Traitor. Terrorist.

The era of mutations and survival!Can Jeremy Night become the hope of the Human Alliance?