
Sooooo...is the baby the emperor’s?

He did. In the novel he'd visit the concubine's quarters once a week or something to fulfill his "duty" as a husband. He didn't want to treat them like other husbands treat their wife so he focused on treating them well and fairly. (spoiler below)
SPOILER
It was phantom pregnancy however so she wasn't really pregnant. But another concubine of his did conceive his child from the novel.

You sure you wanna know? Alright I'll provide two spoilers the extreme and saddest one is at the bottom. Viewer discretion is advised lmao
SPOILER
They got drunk, horny and had s*x one night. ε=ε=(ノ≧∇≦)ノ
SPOILER
From the latest chapters of the novel, Paul had Lucius' baby and Lu confessed to her but this made Paul angry and she felt betrayed. She yelled at Lu why she'd marry him and said, "I don't even love you!"

Hahaha yeah it's the same person just didnt feel like calling his full name
They haven't married yet. They had a one-night stand and Paul was preggy with his child. He proposed and confessed to Paul but she got angry at him. Cuz his confession was practically proving the rumors right. (Rumors that during the war, Paul was called a witch or seductress for seducing Lucius which they both found ridiculous at first but since he confessed, it was practically true) am I making sense? I'm not sure if my head is in the right place yet lmao sorry
...did i miss something...i- I’m just gonna re read it all over again