The manga does a poor job of translating this scene, in the LN Fran tells the orphans that she is the daughter of Karstedt (the knight commander) and she was separated from this family to be adopter by Sylvester, at no points he mentions her commoner backgroundFran just tells everyone the secret that could put Main in danger...
With the type of creep the major was, I'm surprised the boy has managed to survive up until now at all...
The writer's choice to let him Brat Out in a severe case of Big Brother Syndrome to make a "character growth point" for Rosemyne is... Weird.
In the harsh world that they live in the lad would have gotten the snot beaten out of him several times over to make his place in society crystal clear. If he hadn't met with an "accident" to begin with.
Assaulting a high noble? His remaining life should have been measured in seconds. Period.
Rule 1) Never cross a noble.Well Rosemyne is the Saint of Ehrenfest. She's suppose to be a magnanimous individual. Unless they did something to her libray and books, then let the Bloody Carnival begin!