"Metamorphmagi are really rare, they're born, not made."
-- Nymphadora Tonks
Some magical folk have special powers which allow them to do things most Wizards can't do. These magical abilities can be learned in some cases, such as the complicated magic required to become an Animagus. Other such abilities cannot be learned; the Wizard must be born with the powers.
Animagus
An Animagus can change into the form of an animal. The magic for this transformation is complicated and very advanced, and very few Wizards even attempt it. The Ministry of Magic keeps a registry of known Animagi because of the potential for misuse of this skill. When a Wizard transforms into their animal form, some visual clue typically connects that form to the human. For example, McGonagall and Skeeter both wear glasses and their Animagi forms include marks around the eyes.
Known Animagi include:
James Potter - stag
Sirius Black - dog
Peter Pettigrew - rat
Rita Skeeter - beetle
Minerva McGonagall - cat
Arithmancer
An Arithmancer is a person who is an expert on Arithmancy. The word is a combination of the Greek words "arithmetike," which means "of numbers," and "manteia", which means "divination."
Legilimens
A Legilimens is a Wizard who has learned the art of Legilimency, sensing the thoughts of another person. Dumbledore and Snape are both experts at this form of magic. Voldemort is also an accomplished Legilimens.
Metamorphmagus
Unlike some of the other types listed here, Metamorphmagi are born with the ability to change their appearance at will. Nymphadora Tonks is a Metamorphmagus. The word comes from the Greek prefex "meta-" connotating change, "morph" meaning "form," and "magus" meaning "wizard."
Occlumens
The skill of Occlumency allows a person to block the efforts of a Legilimens to probe their thoughts and memories. A person who practiced that rare skill is called an Occlumens.
Parselmouth
The ability to speak the language of snakes and to command them is extremely rare. It is considered to be the mark of a very dark wizard, associated with Salazar Slytherin, who had this ability. Very few wizards are Parselmouths. Besides Slytherin himself, other known Parselmouths include Tom Riddle/Voldemort and Harry Potter. Parseltongue, the language of snakes, sounds like a drawn out hissing without taking a breath.
Seer
Another rare gift is the Inner Eye, the ability to prophesy. A wizard with this gift is called a Seer. Trelawney does have some small measure of this talent, but it has surfaced only twice that we know of. She is, however, the great-great-granddaughter of a very famous and very talented Seer, Cassandra Trelawney.
~PORT KEY!~
