@Glomoro Doesn't matter that the MC is new to the world. When I said "She", I meant it as Penelope's entire existence whether the MC was present or not. Also, I think MC does have memories of Penelope's childhood- at least to some extent. Not 100% sure and I'm not looking to reread atm.
I do remember that when original Penelope first arrived at the house, she wasn't the person she is known in the game for. One of the key memories told to us was when Reynold framed her with the stolen jewelry which then resulted in the loss of favor from all the people of the household. It caused Penelope to stop calling the dad "Father". The servants of the house disrespected her. And even though in-game Penelope was often just defending herself, though not clearly portrayed in the game itself as self-defense, it resulted in her brothers killing her. This one "little bit", I personally find it a very important catalyst to Penelope's personality change. I think the MC said that Penelope started being bossy and greedy because she wasn't being treated like a family and so felt no connection/loyalty/etc towards them. The lack of respect from her brothers and trust from the father made her the way that she is. She was a child who thought she was being saved but instead felt tortured. The one "little bit" that was shown when Penelope was still just a child was enough to turn the tides against her. Imagine being treated with malice at such a young age.
And when I say it doesn't matter that the MC is new, I mean, it doesn't make their 'crimes' against original Penelope any less important. The MC doesn't have to hate them with a passion but she does deserve to be apologized to since there's no longer the original Penelope to be sorry to.
I think, to say that just because she isn't always the focus, therefore the MC doesn't see the whole picture grossly underplays the torture/mistreatment Penelope did undergo. It's true that Penelope isn't an angel (who in the world expects her to when a maid sticks needles in her arm daily) but that doesn't mean the brothers don't need to apologize to her. No matter what, they who had the power to save her remained silent.
This became a bit of an essay lol but I still stand by what I said. I do believe that Penelope changed to be 'villainous' because that's what she felt she needed to become to defend herself.