Sylvia Lost, is not based on any real person or animagi. Most present as a split personality, a state of mind, of my own. I will now give you back story and previous animagi known. The registered animagi are as follows:

Falco Aesalon * — falcon; the first recorded Animagus; the registration system was not in existence in his time.

An Animagus (pl. Animagi) is a witch or wizard who can morph him or herself into an animal at will. It is a learned, rather than hereditary skill, unlike those of a Metamorphmagus. Information on Animagi is taught to Hogwarts students during their third year Transfiguration class.

Every Animagus is required to register with the Ministry of Magic at the Improper Use of Magic Office. This registration includes revealing one's animal form and one's distinguishing markings. The register is available to the public. The primary reason for registration is to ensure the Animagi do not abuse their abilities, as the Ministry is able to keep track of them. A prime example is that, because Sirius Black is an unregistered Animagus, he was able to use his form to escape from Azkaban, as the Ministry did not take this into account when imprisoning him. Peter Pettigrew managed to fake his death and hid from the rest of the world in his Animagus form because he did not register either, and he referred it as an effective disguise to the Dark Lord.

The penalty for failing to register as an Animagus is a sentence in Azkaban, although the length of time is unknown. Rita Skeeter gave up an entire year of writing articles, her main means of livelihood, so that Hermione Granger would not turn her in as unregistered, and consented to writing an article free of charge at Hermione's request. That suggests either a rather lengthy sentence, or the fact that being sent to Azkaban for any length of time is a considerably bad punishment to begin with.

Due to the complexity of the magic involved in becoming an Animagus, they have become very rare. There were a total of seven known registered Animagi in the twentieth century. It is also partially because of this complexity that Animagi are required to register themselves.

Only powerful and skilled wizards and witches are able to become Animagi. The process of becoming an Animagus is long and arduous, and has the potential to backfire and cause the transformation to go horribly wrong. Many witches and wizards simply feel that their time might better be employed in other ways, as the skill is of limited practical use unless one has a great need of disguise or concealment. Once the initial training is over, an Animagus can change at will, with or without a wand.

Animagi can only take on the form of one specific animal. This animal form is not chosen by the wizard, but determined by their personality and inner traits. It may also be that the full-bodied Patronus may reveal what a witch or wizard would turn into if they were an Animagus. For example, Minerva McGonagall, a known cat Animagus, also had the Patronus of a cat. Apparently, the form the Patronus takes may be determined by the same inner-traits as the Animagus form. An Animagus in animal form is also not restrained by the lifespan limit of the creature that they otherwise transform into, seen in the case of Peter Pettigrew, who stayed in the form of a rat for at least twelve years, remaining alive despite the fact that rodents have a short lifespan.

Each Animagus bears an identifying mark on their animal form that is caused by something on their human body. This may be a physical trait like dental structure, or an acquired trait such as glasses. For example, both Minerva McGonagall and Rita Skeeter have markings on their Animagus forms caused by their spectacles, and Peter Pettigrew had a bald spot on his Animagus form from his balding head. If an Animagus undergoes a major physical change, such as the loss of a limb, their animal form will also reflect that, as in the case of Peter Pettigrew missing a finger.