Everything I found in Szarr's palace, for all your fanfiction-writting needs. I haven't found any other post like this one, so i hope i m not copying anyone. Posting it here, because editing the official wiki feels intimidating. Feel welcome to add anything I missed.
Astarion's siblings (the other spawn):
Petras - one of the two you meet in the Flophouse.
Dalyria - the other one from the two you meet in the flophouse. Her diary can be found in the "guest room". Before Cazador turned her, she was a doctor, a "Physician General to the Parliament of Baldur's Gate". She thinks vampirism is a disease and plans on curing herself of it by drinking blood of someone young and healthy - other spawn's daughter, Victoria.
Leon Onufrio - before Cazador turned him, Leon was a sorcerer. He is the one whose daughter's (Victoria's) body is found, cursed, in the room where with the Kozakuran dictionary.
Leon put a protective counter-curse on her, to discourage other spawns from attacking her. Despite his efforts, Dalyria bit her, hoping it'd cure her vampirism. Needless to say, it didn't and Victoria died @easterlingwanderer found out that if you use "speak with the dead" on the body, it turns out that it was a random urchin and Leon did get Victoria out of the city on time. After removing the curse inflicting you with necrotic demage, you can loot a letter of her body from her father instructing Victoria to read said dictionary, so she can freely move around the castle.
In the favoured spawn room, you can learn that Leon was the one usualy occupying it (along with his daughter). His diary reveals that he put extra effort to be Cazador's best hunter, so he can keep Victoria away from others and that he came up with a plan with Figaro to disguise and sneak Victoria out of the palace.
He also notes that he doesnt like the way Violet looks at Victoria and Cazador's wicked smile, when Leon asked him what his master was planning to do with his daughter.
Violet - you can find her Diary in the Dormitory of Spawn. She notes that she put garlic in Yousen bed as a prank.
Aurelia - a tiefling
Yousen - @neophytepagan noticed he is a gnome
Other:
The chamberlain of Cazador was Antwun Dufay. In his diary, which can be found under his bed in his room after a successful passive perception check, it says that he had a lover Lurianna (a werewolf, who can be found dead by walking through fake north wall of chamberlain's office, or through another fake wall in Chamberlain's private room). He knew about Cazador's Black Mass enough to fake his death in order to avoid the threat of taking Astarion's place. Unfortunately for him, it seems he confused the actual death potion and fake death potion, and really died. His lover drank the other potion, which melted her guts. The actual fake-death elixir can be found in his desk, which puts the player in 10-turn coma. He ordered the elixir from Bonecloaks', where he also ordered most of the things the palace needed to function (like bloodstain remover, candles and food for "guests").
Godey - Cazador's right hand. Astarion says that while Cazador was the master of the palace, the kennels (the room where the spawn d be tortured, when they did something Cazador didnt approve of) was the domain of Godey. Godey tortured the spawn when Cazador didnt feel like it. Cazador trusted Godey with the key to the sealed ballroom for the duration of the ritual.
Through the palace, fanatic-servants cleaning the palace: Syrin - human, Greenfern - wood half-elf, Vilhelm - human, Varderola - also human. All of them are servants, who Astarion said are devoted to Cazador and came to the palace of their own will, beggining Cazador to turn them into vampires. Vilhelm is most noteable, as you can talk to him and he asks Astarion why isn't he downstairs, that he is late and the ballroom is already locked. If pressed, he informs that Godey has a key and that the Cazador is going to punish Astarion for missing the ritual (and from his expression, he seems to quite like the thought).
Chamberlain Dufay wrote a blooddonnors ledger, instructing the Spawn to favourite the lower class as prey, as too many missing patriars may drow too much attention.
The language Cazador uses is Kozakuran, from a distant land of Kara-Tur. Astarion notes that they were strictly forbidden from learning it. From Cazador's Journal you can learn that Astarion was not an unreliable narrator when he said Cazador liked torturing him the most: Cazador paid the most attention to him in the journal.
In the favoured spawn room, there is a ledger with the list of spawns who have been favoured (its only Leon and one time Violet).
Amanita Szarr - on her 13th birthsday, invited by her Uncle Cazador. She was invited to the ballroom. She became a vampire, but was not happy about it. She rejected her family name Szarr and named herself Lady Incognita. She claims she stays in the attic and writes stories. One of the books written by her can be found on Cazador's desk.
Mrel Alkam - vampire mastress from Athkatla that Cazador wrote a letter to.
