Counterattack System appeared when I'm already At The Mahayana Realm - Chapter 1 - : Starting 500 Years Late

The heavenly God of Warriors was betrayed by his true love and murdered at the very first night of wedding just because his merits made the monarch insecure. Reborn in a hundred years, Nie Tian would be an appendage no more. Reach the welkin, reverse the fate, reign over the heaven and reconstruct the worlds.

- Description from novelupdates

A supreme expert in the Immortal World had died, and a strand of his soul returned to its original body on Earth. Tang Xiu discovered with amazement that ten thousand years passed in the Immortal World, yet only a single year passed on Earth.

Ruthlessly betrayed by his lover and trusted friends, Tang Xiu found that his soul went back to his previous body on Earth, and, despite he spent 10,000 years in the Immortal World, just a year has passed on Earth and many things have changed. Having an unsurpassed knowledge, Tang Xiu will protect his loved ones and go back to the Immortal World to take his revenge.

- Description from Novelupdates

In an era where humans and demons compete in fierce battles for survival, the Hero has fallen.“…I will take your place.”Thus began the deception of the fake Hero.If exposed, it could mean the destruction of humanity.…But the imposter is just too good at it.[Academia], [Professor], [Hero]

Su Ran, a music prodigy, woke up transmigrated into a book.

At that point in time, the main story arc in the book had already been completed. As a villainess female supporting character, not only did she need to take over the original owner’s pitiful life in poverty, she also gained an instant son right at his rebellious period.

Ten or so more years from then, the son would turn into a twisted, evil villain. He would appear in one of the extra chapters to pick on the male and female lead’s children.

***

Su Ran: Son, you shouldn’t be too outstanding.
Su Han: Why not?
Su Ran: ’cause you will be killed.

Su Ran: Son, would you like to learn music from me and become a zen, little fairy boy who only needs to drink dew.
Su Han: No, I want to go into business so I can support you.

- Description from Novelupdates