Never read the raws, so I can only speculate.
More than likely it *is* as some people expect, and the Emperor isn't as cruel as they think he is. But as Emperor, there are certain expectations of him as well, which is why he had to keep illegitimate children born out of wedlock hidden. As the leader of the Empire, his political position can be threatened by internal enemies who are searching for any weakness of his, and children, illegitimate or not, can be used as chess pieces. However that he named them personally is quite significant. Arien is contradicting herself, but she's also upset. That there's no way he wouldn't know, even if he ignored them all this time, just what does she think ignore means? Well, she's angry and thanks to their environment, mistrustful of everyone, especially their father, so I can let it slide. Strictly speaking if he ignored them, no, he would not know about anything. But he's undoubtedly the type that actually cares, but is bad at showing it, or he wouldn't be so upset at the mere suspicion that there mother abused them. If he finds out the servants had a part to play in their injuries, more than likely they will severely punished and sacked. Their personal reputations so ruined, they'd never find work in the empire again. Or if he really is the monster the children think he is, the entire batch of servants in their castle, will simply turn up dead.