Only Camilla is the bio child of Duke Escar. Ravi is Camilla half-brother, his bio dad was head of the magic tower. Her family downfall wouldn’t have been due to Duke Escar, but due to Aria (the fake Rania) and the Eva Church. It’s thanks to Camilla, the Eva Church wouldn’t succeed in this timeline. Without Camilla, no one would have known about the fake Rania. The fake Rania’s plans might have succeeded because she looks exactly like the previous Duchess and has the one of the kind bracelet that only the previous Duchess had.
Not to mention the Duke Escar would never know about Camilla (Lee Sia) in the previous timelines, since she never left the Fable Empire (she didn’t have a reason to visit the Gracia Empire). He only knew about her being his daughter due to the fact that she had his family heirloom and they have the same eyes. Without meeting her or seen the ring, he would have been oblivious about her existence. He did lose his memory about Camilla’s mother (if he had known, then also forget about the fact that she was pregnant), making him unaware of the promise he made to her.
I wonder if her death was the beginning of her family's downfall in previous life. They executed her themself (and the brother) and if it eventually to be known known the truth that they're the child of the Duke from another county that is no less dangerous individual than her family btw, the two family would clash.