Turns out Vis wasn't merely demoted from Empress to maid. She died and had her soul transferred to some poor woman whose name she didn't even know. Same with Arienora who is now inhabiting the body of another girl Maxwell likely picked off the streets.
The darkness surrounding the imperial family ran much deeper than I thought, with them benefiting from Maxwell's inhumane and unethical immortality research. This explains how the BBEG got ahold of so much political power and influence: the imperial family was indebted to him for "saving" their lives. The emperor owed him for keeping his wife and daughter's souls from being lost to death.
"I'm not the princess!"
Girl, if you're not the princess, then under that logic "Vis" standing before you isn't the empress either. Both of them are technically inhabiting a stranger's body. But I reckon whatever Maxwell did to "help" them was a destructive and irreversible process, so there's no choice left but to live on with what they got. Nothing is going to restore the lives of the two who were sacrificed so they can both live again.
Barring punishment of any sort, I could imagine the imperials trying to hire Laplace as the new head of the court magicians replacing Maxwell. But I'm sure she'd rather continue adventuring with Tanya and the rest of Lilium.