Okay so we all knew the baby's daddy is Maetel. So what am I curious about, before giving birth did Louis tell maetel who might be the father and did Maetel also tell Louis that they had one steamy night?
It would make sense if he thought the duke (or whatever he is) would assassinate her in order to ensure the other princess becomes the heir. Personally, I doubt that other princess is actually the emperors daughter.
If his father really cares for her in the past. Then what happened after learning her daughter's death?
he went crazy and killed everyone or something like that