The Undying Mecha Emperor - Chapter 295 You Are Not Worthy

Once she transmigrated over, Li Haitang, an elite female doctor from the big city, is demoted to a pitiful little cabbage whose parents have both died. She is surrounded by extreme jackals, wolves, tigers and panthers family and relatives. What? She is sold to a half-dead body that is going to be buried in the ground. Has she been sold to an old man with a heavy taste? The only way to escape from the arranged marriage is to pack a bundle wrapped in a cloth! Who would have thought that on the way to the wedding, she meets a wild man who is feared by everyone in the village? The wild man has three treasures, he is hardworking, spoils his wife and has good stamina! His pectoral muscles, abs and mermaid’s line are all there.

- 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.

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

Sulí woke up from chaos without any memories, and without a system on her, simply living through each life cycle indifferently, guided by some mysterious force. Slowly, she realized that in every life, her identity was that of a supporting character with a bad ending...A wife discarded by her husband,The leading student led astray,An ordinary girl taken down by vanity,A childhood friend with toxic tendencies,Romances entangled with embroidered balls,The so-called phoenix men...After countless lifecycles, amassing immense merit and golden radiance, Sulí found out that things were far from being as simple as she thought.

A soul was employed by a higher being to help him manage his world. How will our protagonist live her life to the fullest while also fulfilling her new duties?I don't own Naruto. I adjusted the story to my liking. English is not my main language so don't bother about grammar mistakes too much.