Deicide Learning In A Psychiatric Hospital - Chapter 12 – Goddess of the Night

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

They say in life if you are not at the top of the food chain, it's only a matter of time before it becomes your turn to be prey.They say only the strong can survive in the Murim, I and my little sister after getting transmigrated survived painfully, fighting and fighting, climbing our way to the top, protecting her every step of the way.We finally found ourselves at the top of the food chain, at the top of the Heavenly Demon Divine Cult.But life just had to be so cruel, a plot out of jealousy got I and my sister killed, I watched her die in my arms and I could do nothing but just painfully watch.But maybe life wasn't as cruel, it at least gave me a chance to exact revenge.I was reborn into the Unorthodox faction.This chance shall not pass me by.Anyone or anything that stands in my way...I shall burn...I shall massacre...I shall Destroy...

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

At 3 years of age, her father went missing. At 15, the muscle in her hand snapped. At 16, her mother passed away in a car accident. At 19, she was framed by her uncle. At 22, she was burned alive by her newly- wedded husband and her best friend. Perhaps it was God’s sympathy that allowed her to return to the time when she was 15 years old to re-live once more. The previous lifetime of being low- key and having forbearance resulted in betrayal and misery. In this lifetime, she must be lofty and domineering to let those who have bullied her suffer a terrible end!

- Description from Novelupdates