
That was the BEST assessment of this story I've read yet!
As for the half-brother I think he's older. The story says she's second in line and I highly doubt that it would mention the status of her line to the throne at all if women were considered secondary to men. I mean her brother could marry a woman who would give birth to male heirs and then she would be even farther down the line of inheritance, if that were the case.
And the only way Apollonia could be older is if her mother had been in love with someone else before this guy. Given that the story they made up about her mother meeting Gaius in secret wouldn't make sense if Apollonia was older and still Gaius' daughter. They would have had two children but only one was ever mentioned in that made up story. Highly suspicious. Or that I don't think the mother would marry or get together with someone she didn't love, especially when I read how she tried to make the current emperor look at her because she loved him so much. Yet if that's true then the fact there is no mention of a previous lover is something else that is utterly suspicious.
Further to the point about the FL's mother not having a previous lover, neither Apollonia, Elenia nor the story has ever referred to Gaius as anything but her father.

Thats true cuz apparently her mom was going to become the next ruler and no one objected it so its most likely normal for her kingdom...hahaha but of course her concubine father is a greedy misogynistic piece of trash. Well the brother could do that but in the end he, his would be "heirs" and their father are not legitimate heirs they don't have a drop of the royal bloodline so it would only be a matter of time before they got overthrown not to mention they secretly killed the emperor and the crown princess saying it was an illness that killed em, if the people of her kingdom found out they would force her father to abdicate n he would prob get the death sentence or they would rebel. Well whatever happens usurpers usually don't have good endings, I can't wait to see her take sweet revenge. ლ(´ڡ`ლ)

Her mother gave up her right (which does indeed imply that no one had a problem with her being a woman taking over the reins) to the throne, presumably to hand it over to Appolonia's uncle. One of the reasons Elenia took Paris in was so that he could help Elenia's brother become emperor after all. But we never are told if Gaius killed Appolonia's uncle or not nor are we ever told anything else about the uncle. I'm assuming that he's either a wastrel or that legitimacy to the throne is determined by the direct line of descendants since her Grandfather claimed Appolonia as his heir not his son. But then why did Elenia want her brother not her daughter to be the ruler? Maybe she wanted her brother instead of her husband to be the temporary emperor?
Yeah I get the reason that the FL's father took revenge, but he not only hurt innocent people just like his father-in-law apparently did but he is also misogynistic af. So no sympathy from me.
wow its rare to see an actual complete handsome scum father in these types of manga usually they end up realizing they shouldnt project their hate onto the kid and try to make up for what they did to them but he is just...irredeemable his entire family is scum... also i wonder if he was already married to her mom at the time he fell in love with MCs half brothers mother...cuz if he was then i can see y her grandfather got so angry...but regardless if the grandfather really was in the wrong he shouldnt have betrayed n killed her mom like tht she was innocent. but then again hes one power hungry mofo that wasnt satisfied being a prince consort n didnt like the idea of a woman being the Ruler. UGH I really dont like him and his greedy ass family I hope the MC has NO mercy and wipes them out (╯°Д °)╯╧╧