Toaru Majutsu no Index - Volume 18, Chapter 5: The Mercenary and the Knight’s Encounter and Clash. Another_Hero.

Xerox Zee had always thought of himself as an ordinary guy—just another face in the crowd. That was until his 18th birthday when his System finally gets Unlocked!.The System revealed a shocking truth: the world he lived in was exactly the same as the plot of a novel he had once read!But instead of being helpful, this turned out to be a big problem.Main Character : “I’m meant to save the world and become the strongest. Everyone else is just there to help me along the way!”Xerox Zee : “Hold on... am I just one of those people there to make him look better?”It seems like I'm just a stepping stones!

A good-for-nothing man married a beautiful girl but was kicked off the bed on the wedding night. Furiously, he wrote a bill of divorce and ran away.
He was schemed a car accident in which he nearly lost his life. However, it turned out to be a blessing. He swallowed the soul that passed through the outer world, thus obtained superb medical skills and martial arts.
Later on, with the silver needles and invincible martial arts, he embarked on the road of counterattacks and was committed to his great dreams.

- Description from Novelupdates

After an unexpected death, a soul finds itself reincarnated into the body of Itsuka Shido, an ordinary teenager in a world filled with powerful spirits, magic, and dangers from other dimensions. With the help of a mysterious system integrated into his body, Shido gains the ability to travel across worlds, summon legendary anime characters, and unlock a wide array of random skills and abilities.Disclaimer: The cover isn't mine, credits to the original artist.

Luo Jing traveled through, and traveled to the outer door of the Demonic Soul Refining Sect, and became a miscellaneous fish disciple.

There is a powerful senior sister in the door, who has been pestering him. Just when Luo Jing was thinking about whether to “be sensible” and practiced at night, he found that his girlfriend had also crossed over with him, and the two could meet in a dream.

The girlfriend actually traveled to the Immortal Gate of the Right Way and became the direct disciple of the elder of the Immortal Sect.

Shen Qingxuan: Can you stay away from those demon girls?

Luo Jing: I’ve tried my best to stay away from them! It was they who wanted to make me a stove, and I didn’t want to!

This book is also known as “My Husband with a Demon-sucking Female Physique”, “In order to keep my boyfriend, I must practice hard”, “My fairy world can’t be a long-distance relationship”

- Description from novelbuddy