Chapter 1
Introduction of my Harry Potter OC
Full name: Cassiopeia Adhara Black
Fancast: Anna Popplewell (Chronicles of Narnia)
Summary of her character: to put it bluntly, at the start, Cassiopeia will be the complete polar opposite of her twin brother Sirius. She will initially believe in her parents' pureblood teachings because before Hogwarts, those teachings would be all that Cassiopeia would know. Growing in the Black Family home, Cassiopeia would be very close to her oldest cousin Bellatrix Black and her little brother Regulus. As much as she would try to be close to Sirius, the two would just be too different when it comes to personality.
It wouldn't be until coming to Hogwarts, being the first Black sorted into Ravenclaw, and her family being disappointed would upset her, though she'd try to not let it show. It wouldn't be until one of her fellow Ravenclaws, a half-blood named Emmeline Vance, comes up to her, genuinely asking if she's okay that she finds herself breaking down in front of her. Slowly, but surely, befriending several other fellow students, especially the "wrong sort" in muggleborn Lily Evans and half-blood Remus Lupin, would open her mind to new ideals and teachings. For the first time since their early childhood, Cassiopeia would grow to understand how her twin brother Sirius saw things.
However, it won't be until the summer of 1972, the summer before her second year, the night Andromeda is disowned, and Bellatrix proudly reveals her Dark Mark, that Cassiopeia's rose-colored glasses would fall and the reality and truth about her family would set in. She would no longer see her parents or Bellatrix in the same light she did before.
TV-Tropes
Action Girl: after graduating from Hogwarts in the summer of 1978, Cassiopeia becomes this both during her time with the Order of the Phoenix and working in the Ministry to try to combat against the anti-werewolf laws.
Aloof Dark-Haired Girl: this is how she starts out initially. She will grow out of it but it will take time.
Battle Couple: becomes one with Remus during their time in the Order.
Beware the Quiet Ones: Despite being very soft-spoken, ladylike, and stoic, she can and will fight back if pushed hard enough, whether it be Voldemort's followers or Wizengamont members who want to push forward more anti-werewolf laws. Even while up against people like Umbridge, Cassiopeia never once loses her cool.
Brainy Brunette: The main reason why she's sorted into Ravenclaw. Even as a first year, she has a very political-esque mindset, having plans to join Wizengamont.
Big Sister Instinct: Despite being disowned and not seeing him in quite some time, Cassiopeia still worries a great deal about Regulus. She also has this instinct towards Lily, Marlene, Dorcas and Mary.
Broken Pedestal: Seeing her oldest cousin Bellatrix, someone she once looked up to during her early childhood, proudly show off her Dark Mark after Andromeda's disownment, completely shatters Cassiopeia's heart.
Character Development: Cassiopeia will go from a meek, mousy girl who believes in what her parents taught her for many years to an Action Girl, willing to take on both Voldemort's followers and Wizengamont in order to have peace.
Deadpan Snarker: after her Character Development, her snark does come out subtly, especially when she snarks at Sirius.
Despair Event Horizon: after being disowned along with Sirius, Cassiopeia enters this, being practically catatonic for the entire summer. She does get better but the damage would still be there.
Hidden Depths: even before her Character Development, deep down, Cassiopeia would ponder if her parents were actually right about their teachings but she never voices these thoughts out-loud.
Icy Blue Eyes: has these eyes prior to her character development.
Team Mom: more like Team Big Sister, but Cassiopeia is definitely this for the Marauders and her own group of friends, often waiting for the Marauders after every full moon.
When She Smiles: the first time she smiles--an actual genuine smile-- when with Remus, her friends take note of this.
Wise Beyond her years: due to her political-esque mindset, Cassiopeia is very elegant, wise, and soft-spoken, even as a first and second year.