I'm the Villainess in the Apocalypse - Chapter 459. Reunion

The unparalleled Demon King Ye Xuan, who was able to heal the death or the living alike and holder of the medicine Holy Scripture, was betrayed and killed by his fellow Demon Kings. But he reincarnated into the body of Ye Xuan, the prodigal son of the Ye family and vowed to himself that he would return to his peak and take back everything that belonged to him!

- Description from Novelupdates

Liv Hamelsvoort, who bears the label of the ‘Fake Saintess’ and is the laughingstock of high society for her unrequited love for Duke Lartman. No one could understand her, but she likewise couldn’t understand them.“I’m in the middle of enduring the love of the gods.”There was a world that ordinary humans couldn’t dare to comprehend.“Who harmed my child?”“Does my child not exist in this world?”“I don’t need a world where the child I love doesn’t exist.”The moment the enormous things she had been bearing were revealed, Liv’s life finally began to change.“I will love you in any timeline, Your Grace.”Liv was content as long as she could continue loving. But if she wanted to protect that love, she had to change; the world was whispering that to her.

Roy’s life was nothing special. The only thing commendable was the last few moments when he saved a mother and her child from a drunk driver.
…
It’s really an egg! Damn it, what kind of monster have I become? Did I fall into Hell instead of making it to Heaven??
Join Roy as he ventures through various worlds with the Custom Made Demon King System—a system that allows Roy to draw anything he can imagine and create it through exchanging souls!

This is a story of Xia An, a transmigrator from the end of the world, who transmigrates into the body of a cannon fodder who was the mother of the villain.

- Description from Wattpad