This article contains plot details from the latest book.
In order to swear fealty and become members of the organization, Sophie and her friends had to lick a fist-sized black cube for DNA and say the oath "I will do anything in my power to help my world" until the cube decided that the speaker was sincere. According to the book Neverseen, it only took Sophie one try because her spot was reserved.
There are four known hideouts: The High Seas Facility, Alluveterre, Brumevale, and Watchward Heath.
The Black Swan are the ones who created Sophie as Project Moonlark, they genetically enhanced her to be able to have several different special abilities. Prentice, their keeper, had his mind broken and was sent to Exile. Mr. Forkle became Sophie's neighbor and called the hospital when she hit her head. Mr. Forkle then triggered Sophie's ability as a Telepath at, incredibly, the age of five. It is not entirely clear what they made Sophie for, but we know it is for good. Then, years later, we know that Sophie became Keeper.
One of the leaders of the group, Mr. Forkle, was Sophie's neighbor in the Forbidden Cities. When the Neverseen kidnapped Sophie and Dex, Mr. Forkle came, took Sophie and Dex to Paris, activated two of Sophie‘s abilities, Inflicting and Polyglot-ing, and trusted that they would find a way back to the lost cities on their own, but the Neverseen found Sophie and Dex again. It was the Black Swan that set up the necessary elements for Sophie to catch the Everblaze burning in the Forbidden Cities, using Gildie, the flareadon, and Prattles pins.
The Black Swan started leaving clues for Sophie. She and Keefe went to the Black Swan so Sophie's abilities could be fixed, which they did so with a small dose of limbium. This allowed Sophie to heal Alden Vacker's broken mind. When the Neverseen found the cave and tried to kidnap Silveny the alicorn, the Black Swan fought them off, allowing Sophie, Keefe, and Silveny to escape.
The Black Swan helps them plan an ambush on Mt. Everest. Mr. Forkle helped Fitz get Sophie's trust so she would allow him into her mind. At the end of the book, Sophie, Fitz, Biana, Keefe and Dex decide to go find the Black Swan to join them and rebel against the council.
Mr. Forkle, Sophie and Councillor Oralie go to interrogate Gethen. Mr. Forkle also attended the Peace Summit as a representative of the Black Swan. Later in the book, after the Peace Summit, Mr. Forkle's identical twin is stabbed.
Book 6: Nightfall
After the death of Mr. Forkle, the Collective reveals the truth that Mr. Forkle has an identical twin who has helped him keep up with having so many identities. After his death, it is a struggle for Mr. Forkle to be able to stay on top of all three (and possibly more) of his identities.
Mr. Forkle - (as of Nightfall) aka Magnate Leto and Sir Astin: (one twin deceased, other alive) The head of Project Moonlark and leader of the Collective. He was thought to be dead but was it was revealed that “Forkle” was actually two people taking turns assuming his identity. The Forkles were twins, but one of them was killed. Forkle is a talented telepath.
Jolie Ruewen: (deceased - see Wanderling Woods): A double agent for the Black Swan who worked against the Neverseen, but was killed by Brant, a Pyrokinetic of the Neverseen. She hid a report in Havenfield for sixteen years before Sophie Foster uncovered it. A Conjurer.
Prentice Endal: The Keeper for the Black Swan and the father of Wylie Endal. His mind was broken by Quinlin Sonden under the order of the Council. Imprisoned in Exile afterwards, he was saved by Sophie Foster, Dex Dizznee, Biana Vacker, Keefe Sencen, Fitz Vacker, and the Collective. Currently residing in the Stone House for rehabilitation. A Telepath.
FITZ VACKER: (as of Neverseen) Fitz is a Telepath and Sophie's Cognate in training. He is one of the only members of the Black Swan that can read Sophie's mind. He also is Sophie's main love interest in Flashback.
KEEFE SENCEN: (as of Neverseen) An Empath. Sophie and Fitz's friend. He worked as a double agent for the Black Swan against the Neverseen a short while which resulted in catastrophe but managed to steal both Fintan's and Kenric's caches, which were revealed to be fakes in Flashback.
LINH SONG (as of Lodestar) A Hydrokinetic. She was the elf that flooded Ravagog after stealing the "cure" for the gnomes, and prevented the flooding of Atlantis during Lady Gisela's escape. She is also Tam's sister.
COIFFE - aka TIMKIN HEKS: He is Stina's father and Vika's husband. He is Talentless. When he works with the Black Swan, he disguises himself by wearing fur all over his body, making him look like a poodle.
PHYSIC - aka Livvy: a physician who heals Fitz after he is injured while rescuing Prentice. She used to be part of the Collective before stepping down for Juline to take her place. She is also Quinlin's ex-wife.
“I will do everything in my power to help my world.”