Scarlett (Ishtar)

Obvious 'I don't support the author's views' etc but I've had this HP OC since I was a little kid so she's going on my profile

Ishtar Black (later Ishtar Granger) was Bellatrix's child, but Bellatrix didn't want to have a child and gave her to Narcissa to raise. Ishtar became the shameful family Hufflepuff that everyone disowned (except Narcissa, they kept in touch) and she fell in with Harry and his friends instead. Later in life, she would marry Hermione and work with magical creatures.

This is the 'really short summary' version obviously

House: Hufflepuff

Wand: Redwood, unicorn hair, 11 inches

Patronus: Black stallion

Trivia:

• She's always had the scars on her face, ever since early childhood, but she can't remember where she got them and Narcissa won't talk about it. She can see thestrals, but she hasn't made the connection yet
• The sorting hat wanted to place her in Ravenclaw, but she insisted on Hufflepuff because she wanted to choose to be kind above all other virtues
• Ironically, she used to look down on muggle-borns, because that was the attitude her family raised her with. Not very kind. But when she actually met muggle-borns at Hogwarts, she realised that she was very wrong about that and tried to make up for her previous outlook- the sorting hat knew she had the capacity to change and do better

The slightly longer version:

Ishtar was born to Bellatrix and- I assume- a Death Eater that Bellatrix never revealed the identity of. Bellatrix wasn't interested in having a child, so she gave the baby to her sister Narcissa, who had just had her son the year before. Narcissa raised Ishtar alongside Draco, and tried to give Ishtar somewhat more attention to make up for the fact that Lucius and Draco effectively ignored her since the day Narcissa brought her home. Consequently, Ishtar grew up feeling close to Narcissa, but not to the rest of the family.

When she was old enough to go to Hogwarts, she was sorted into Hufflepuff. That was the last straw for Lucius, who cut her off completely, and told Draco not to associate with her at school. Narcissa secretly kept in touch with Ishtar, but otherwise, she was effectively alone at Hogwarts. She fell in with Harry and his friends as she had some classes with Ginny, since they were the same age.

Ishtar showed an aptitude for charms, but usually wouldn't use her talents for anything useful, preferring instead to play jokes on people (surprisingly, she did not get along much with Fred and George, finding them too foolish. Evidently, in her mind, there was a line). She had a laid-back and thoroughly unserious personality, something that put her at odds with Hermione, who was the opposite. Over time, they began to influence each other for the better; Hermione convinced Ishtar to take things more seriously and work harder, and Ishtar got Hermione to relax a bit more and have fun every once in a while.

Meanwhile, with trouble brewing, Ishtar had to decide if she would stand with her family or stand with her friends. Draco didn't even try to influence her- she thought he didn't care enough to even want her on side, but in fact Draco was trying to let her make her own choice, in his way. As things at Hogwarts got scarier, Ishtar began to take a more active role in fighting back.

[adding more later or something]