Nicholas Malfoy had always fit the Malfoy family image perfectly, believing to outshine the members who did not. A cunning and ambitious man who - of course - was apart of the Slytherin house. He was not one to be ashamed of his magical ability, and was actually quite proud of his skill. Though, his intelligence shouldn't be forgotten. Overall, Nicholas stood well to his family's name, and planned to stay that way when he began to date the wealthy pure-blood witch, Ophelia MacMillan.
The two had a decently healthy relationship and overtime, Nicholas even set a date on when he would propose. Though, a problem would arise when Ophelia revealed she was pregnant - with his baby, of course - a month before Nicholas planned to propose. So, to avoid any family scandals, they didn't get engaged a month later. They got married. They did love each other, so a quick marriage didn't affect the relationship in a bad way. Though, the birth of Sebastian some months later was not when they imagined they would have kids. So, there was a decent age gap before the next one was born.
Out of all his children, it was clear that Nicholas favored Sebastian. The oldest son that was practically a spitting image of his father, inside and out. So, it always seemed that the eldest' achievements were celebrated much more than some of the kid's. (Even when Nicholas's daughter, Theodora, married into the royal family... Although, after that, the two didn't keep much ties with each other.) Though, even with favoritism, Nicholas and Ophelia made it their duty to try and teach their children one thing. The belief in blood supremacy and to never marry below a half-blood. Whether or not they would like to be an embarrassment to family name, that was up to them.
With being put in the spotlight all the time, Sebastian made sure to make his family look just as good as when Nicholas had done it. He did well in school, his father's magical skill and intelligence being passed down. And, of course he was a Slytherin. Some may even say Sebastian made a bigger impact on Hogwarts than Nicholas, being that he was a prefect for his sixth year.
Although Nicholas had a favorite son, he had a least favorite son who was Leonardo. Leonardo had never fit the family image, being sorted into Gryffindor and not agreeing with his family's stance on blood supremacy. He was an outcast in his family but found acceptance within his house at Hogwarts, and also became romantically involved with another pure-blood. After graduation he eloped with Margo and left his family, not wanting anything to do with them.
Once Leonardo started having kids, his brother tried to reach out to him but Leonardo was too angry to speak to them. It wasn't until Penelope was five that Margo convinced Leonardo to speak with his brother again, and while it wasn't that much of a mend to their relationship they promised that their kids would grow up together.
Penelope grew up surrounded by her cousins and grew close to Heloise, not really understanding about the rest of her uncles/aunts and how the Malfoy's were supposed to be. She grew up thinking everyone was fine and normal, and didn't really think much about it.
Penelope's first sign of magic appeared when she got into a fight with Heloise when they were 7. The two were arguing about pure-blood's and muggles because Penelope was friends with a muggle, and in her anger her magic caused Heloise's mouth to sew shut. She was so mortified that she didn't talk to Heloise for the rest of the summer.
Penelope got her Hogwarts letter and was sorted into <insert house here>. Of course she was ecstatic, but she felt a little left behind as the rest of her cousins got sorted into Slytherin. She understood why her family was distant from the others, and wished things could have been different.