So, am I reading page 6 right, the King/Emperor is the four kids Uncle. It said his sister the Queen, after mentioning Johannes?
That might explain why the King/Emperor supported the Stepmom in the past. As it would not be tough for Johannes to ask his brother-in-law to do this for him, in case of his death. Though, it also says something about Johannes's siblings where he has one decent one and a bunch of greedy money grabbers. Then again, it is tough to be greedy about a Marquis's inheritance when one is married to the King/Emperor.