I Accidentally Adopted The Villain’s Daughter [Bl]

After he died in his previous world, Lucian get transmigrated into his best friend favourite novel world and became the main character brother who has a same name with him.

He thought it would be fun at first but he was wrong. He encountered a lot of hardship while he was growing up.

He decided to live peacefully with a mysterious baby that appear outside of his bookstore doorstep. He raise her like his own child.

5 years later, the real father of the child appear out of nowhere and telling him that the child was his. The real father is actually the villain of the novel. What would Lucian do?

[I will edited the synopsis again if necessary]