- "'You don’t need to ask me questions. Let’s not delay the Sorting for those too insecure to know their house already! Put me in Slytherin!"
- —Seneca to the Sorting Hat in The 1884 Sorting
Seneca is Lucius Lestrange's youngest daughter and the baby of the family. When she was six it was discovered that she is a metamorphmagus, a power that she is still learning how to control but is definitely a lot better at it than she was in the beginning.
Seneca was born on the very first day of 1873, as the fifth and final child of Lucius and Alexandria Lestrange. Since she was just another girl, Seneca was overlooked during the majortiy of her early years. Her metamorphic abilities would show up, but they'd change her appearance in such subtle ways and so infrequently that they went unnoticed.
As she grew up, some of her nannies and governesses would make note of the changes, but since they were not quite as booming as such displays tend to usually be, they either thought that it was a game of the lightning or that their employers probably wouldn't take them seriously anyway if they told them. When she is two, her governess at the time noticed that her eyes had changed from hazel to light green and actually does speak up about it, but everyone assumes she was overreacting since hazel can pass for green under certain lights.
All in all, as a child, Seneca would creep out her governesses, both because they would notice that there was something different about her at times but they could never tell what or explain why and because Seneca's polite disposition gave out creepy child from a horror movie vibes.
Finally, when she was six, Seneca made a change to her appearance that couldn't be overlooked. Seneca changes her hair from blonde to green and she is then made to change anything she wants from her appearance, just so they can double-check that it is actually what they think it is and not some sort of simple sign of magic (one of which she had displayed only a year ago).
With her metamorphic powers being confirmed, Seneca becomes much more aware of them herself. Previously, she didn't even know what a metamorphmagus was and while she did notice that a lock of her would change colours and such, she always assumed that it was something all wizards could do. This awarerness for her installs some sort of insecurity about her powers in her, which she'd have for years to come and still has to an extent.
The Shark Animagus AttackEdit
In March of 1883, while enjoying a boat ride in Padmore Park, Seneca, along with many others is attacked by a shark animagus who wanted to have some fun.  Her governess' quick reflexes thankfully saves both of them and unlike others they make it to the shore alive, without any limb missing. Seneca is shaken by this attack, but not that much so as for it to ruin boat rides for her. In fact, after the incident, Seneca would even joke about it.
Later in the year, most particularly in July, Seneca and her closest friend Gretchen Lestrange are kidnapped. The two were at Honeyduke's, when their kidnapper approached them and posed as a Honeyduke's employee. Both Seneca and Gretchen are fooled by him and when he supposedly helps them locate some candy they were looking for he grabs hold of both of them and disapparates from the shop.  
The man in question was Kevin Trailor, a muggleborn Quidditch player whose dire need for money had made him desperate enough to attempt kidnapping a Lestrange. He takes the two girls to a house in Godric's Hollow and after he accidentally slips their location to the girls, they manage to subtly add their locations to the letters he told them to write their fathers. 
It doesn't take long for Orestes and Lucius to locate the house and the two girls were rescued. As for Kevin Trailor, he was tortured and then killed.  To the public, a different story is told. The girls were supposedly taken to London, where they managed to escape through an open window and some kind unnamed gentleman helped them find their way home. 
Padmore Park's FlasherEdit
In May of 1884, Seneca falls victim of a creepy person in the park once again, though this time it is different from almost being killed by a shark. She and her sister Tullia had been feeding ducks and enjoying a rather pleasant conversation for once, when they are approached by a raggedy looking man. First he verbally abuses them and then proceeds to flash himself to the girls, which rather shocks the innocent Seneca. Tullia is quick to act and uses her wand to send him away. The event causes for the sisters to briefly bond, but they are back to their usual bickerings soon enough.
Seneca was the one from her siblings to take after their mother's appearance most. Instead of the typical dark Lestrange hair, Seneca's is of a much lighter colour, though hers is still a darker blonde than her mother's. Seneca is also the only one from her siblings to inherit their father's hazel eyes, with Claudius' being green, Valeria's brown and Tullia and Cash's blue. She is not really typically beautiful - in fact, in many ways Seneca could be considered the plainest of her sisters. She is taller than most eleven year olds, at four feet ten inches and she is overal more mature looking, often passing for a year or two older depending on how she styles her hair and what she wears.
Personality and TraitsEdit
Seneca is a quiet and subtle person. She received an upper class upbringing, so she holds herself with a grace and poise that only someone in the upper class would possess. She was always a well-behaved young lady and her governesses had little to complain about where her personality and behaviour was concerned.
Seneca is ambitious, though her ambitions tend to extend to her wanting to be better than her sisters for now. Her father is perhaps the most important figure in her life and she views him in an almost worship-y kind of way. His approval is everything that matters to her and she strives to live up to his expectations. This loyalty of hers makes her agree to everything he tells her to do and she never understands it why any of her siblings might want displease him.
Her loyalty for her father aside, Seneca is not the kind of person to put herself after others. In fact, she can be somewhat selfish. She has a sense of self-preservation and while she would be willing to take a risk to help those close to her, in the end she'd most likely choose to save herself than someone else. That is not to say that she is the backstabbing sort, but she is certainly not exactly self-sacrificing.
Seneca's closest friend. Gretchen is Orestes Lestrange's second daughter, making her Seneca's first cousin once removed. Despite her having an older sister Seneca's age, Frida, Seneca always preferred her over the older girl. Maybe it was because they bonded over being the only blonde daughters. Maybe it their love for anything girly, pink, cats and Lady Macbeth. Seneca and Gretchen have similar personalities, with their plotty ways and after they were kidnapped together they became even more close.
In March of 1884, the two kidnapped a maid  in order to interrogate her about the details of Hogwarts' sorting. It was their first real display of plotiness, as they made it seem like she had merely fallen down the stairs, only to wake up on the chaise lounge in Seneca's bedroom after the two of them were "considerate" enough to take her there.
OOC they are known as Princesses of Plotting, or PoP.
Seneca's father. He is perhaps the most important figure in her life, at least where role models are concerned. Seneca loves her father to pieces and she's fiercely loyal towards him. This loyalty of hers, combined with her special abilities and good behaviour have granted her his favour which she never plans on losing. Seneca strives to live up to his expectations and she secretly views her older sisters as threats. She is oblivious to anything bad he might have done and she could probably catch him murder a baby and still think that he was the best person ever. She exclusively calls him Papa. She'll probably call him that even when she's forty. HE WILL ALWAYS BE HER PAPA.
Seneca's second oldest brother. Generally, Seneca always got along better with her brothers rather than sisters, probably because she didn't really view them as threats. The two always got along, but they truly bonded in the summer of 1884, when she forced him (politely, of course!) into boat rides with him.
She ships him with one of her friends. Preferably Vesta. OOC they are known as Sash.
Seneca's second oldest sister. The two had always been antagonistic with each other, which probably mostly stems from how similar they are. In a way, they are the halves of the same coin. They're both ambitious, they're both clever, but Tullia just happened to be sandwiched between her siblings and get sorted into Hufflepuff, whereas Seneca happened to be born with the special powers and always sucked up to Lucius.
Even if they bicket, they still care of each other, even if Seneca might deny it until the day she dies. OOC they are known as Sellia.
Seneca's oldest brother, who she adores. Due to their large age gap, Seneca and Claude were never as close as they could be. Still, Seneca interacts with him much more often than other girls with older brothers do. The two have a tradition of sorts of him taking her to the New Year festivities for her birthdays.
Seneca's oldest sister. Valeria would always serve as an example and a role model to Seneca while she grew up. Nowadays, Seneca views her antagonistically and she wants to become even better than her. With that being said, Seneca does enjoy spending time with her sister and she doesn't really hate her. She just wants to be better than her.
Cash's old betrothed. Seneca and Kayline always got along and Seneca thought that she and her brother made and excellent match. She was very saddened when she died of the Laughing Plague in the summer of 1884.
One of Seneca's closest female friends other than Gretchen. The two will begin their first year at Hogwarts together and Seneca hopes that they'll be sorted into the same house.
One of Seneca's future Slytherin yearmates. They have not actually met yet, but SENECOTTA <3
A middle class girl, she and Seneca had occasional meetings around shops before they entered their first year at Hogwarts. Seneca does not particularly like Nyneve, but she also doesn't really dislike her as much as she could. The two are likely to have an awkward sort of "friendship" as their Hogwarts years go by.
Seneca's cat from 1882 to 1884. Iris was a magical breed of cat, whose fur would change colours. This power of hers resembled Seneca's own metamorphic powers which was what drew her to Iris in the first place.
Iris died in the summer of 1884 , after protecting Seneca from an adder. Seneca was crushed by her death.