I don't remember the full details but possible SPOILER:
SPOILER (read at your own risk)
Please correct me if I'm wrong but I think she was subjected to abuse too (?), that's why she's so feeble. She also gets an unfortunate ending so if there's anyone to feel sorry for, it's her.
NOOO she doesnt get a happy ending?!?!?!
Spoilers again:
I reread the spoiler thread and copy pasted some replies. (Also I was wrong, she wasn't abused but she experienced something traumatic at an early age). Here are the relevant parts about Agnes:
https://forum.novelupdates.com/threads/golden-time.62280/page-2
"i think she's the most pitiful character here. she is jessica's sister but those two are totally different. the reason she became like that is when she was five she saw her mom suicide. that's why she often had tremor when dealing with people
and she don't have happy ending.. :("
https://forum.novelupdates.com/threads/golden-time.62280/page-4
"She’ll come to Earl’s World safely but then being as timid as she is, she’s always being bullied by Nefarna’s princesses Michaela & Juana who are backed by their aunt Katrina.. Moreover Katrina hates Northeon deeply due to their first night ceremony in the past
Frédérick will come to Imperial capital too to look for Jessica.. He planted spy among Agnes’ maid and then one day before his departure to go back to Northeon, he sees Agnes in different manner (straight back, happy steps).. It’s when Agnes ignores her promise with Alex to not visit Jessica in the safe house anymore
Frédérick follows her and finds Jessica.. Agnes who feels guilty for holding Jessica’s ankle every time, decides to stab her chest with Frederick’s sword"
"Agnes’s death is the last push to make Jessica realizes that she’s indeed the true successor of Northeon. Her father educates her with the successor’s standard and all the way she needs is her own will. In the middle of escape from Frederick pursuit, Jessica then decides she will take Northeon’s throne herself."
I added the links so you could read the thread too, if you want more info. ╥﹏╥
NEEOOO MY POOR AGNES AND JESSICA NOOOOOOOOO
RIP to a good girl ┗( T﹏T )┛
Boy I rlly do hope the fragile bug sis is the one who'll kill Fredrick and I dnt want her to be evil I just want her to have more confidence man I wish her parents never coddled her so much
She should've been a big sister to be prod of to her little sister so that never had to hear those words