Counterattack System appeared when I'm already At The Mahayana Realm - Chapter 542 - 543:

One day, Zhang Fan, a poor medical student, receives a medical system from the future. This turns him into a new shining star in the medical field. Along the way, he must face medical corruption, competition, and infighting from other doctors, and even find time for a love life as he strives for the top of the medical field!

- Description from Novelupdates

Vergil, a 21-year-old young man, leads an apparently simple life in a somewhat troubled world. His family is also simple—although his father is no longer alive, his mother has always been by his side, despite being a bit... aggressive. But that's not so unusual nowadays, right?Everything changes drastically when Vergil, after an unexpected death, awakens as a demon. To his surprise, he discovers that he has accidentally married beautiful Pure-Blood demonesses.Now, he will discover how the world really works from a Demon's perspective.

Suddenly, the unmarried twenty-year-old Ye Zhizhou had many more relatives, yet it was too late for him to clearly understand the circumstances as he nearly died in a car accident. After that, he somehow managed to survive and was even forcibly bound to a Salvation System.

“W-w-w-welcome to the simulation zone.”“New user recognized.”“Proceeding to register...”“Please wait...”“Register complete.”“Welcome, user number 4956: Evan Rotewed.”In a world of mana, those without reserves for it gets left behind. Rules and regulations are set to categorize everything into neat piles, each promising the highest potential a person with mana can get. Starting his life at the rock bottom, Evan Rotewed swore he will rise above it all, even if he had to break the ironclad system the entire world holds close to its chest. Wave a hand to the broken reflection beyond the mirror of ones and zeroes. System Discord.