Count Olaf is the primary antagonist

Antagonist

An antagonist is a character, group of characters, or institution, that represents the opposition against which the protagonist must contend...

 of the children's novel series A Series of Unfortunate Events

A Series of Unfortunate Events

A Series of Unfortunate Events is a series of children's novels by Lemony Snicket which follows the turbulent lives of Violet, Klaus, and Sunny Baudelaire after their parents' death in an arsonous house fire...

 by American author Lemony Snicket

Lemony Snicket

Lemony Snicket is the pen name of American novelist Daniel Handler . Snicket is the author of several children's books, serving as the narrator of A Series of Unfortunate Events and appearing as a character within the series. Because of this, the name Lemony Snicket may refer to both a fictional...

. In the series, Olaf is an actor

Actor

An actor is a person who acts in a dramatic production and who works in film, television, theatre, or radio in that capacity...

 and is known to have committed many crimes as a member of the fire-starting side of V.F.D.

V.F.D.

V.F.D. is a secret organization within the book series A Series of Unfortunate Events by Lemony Snicket. The purposes of the organization are never made clear, although the name of the organization is connected to various interpretations of the word "fire." V.F.D...

 prior to the events of the first book in the series. Olaf is repeatedly described as having a unibrow

Unibrow

A unibrow is a "confluence of eyebrows"; that is, the presence of abundant hair between the eyebrows, so that they seem to converge to form one long eyebrow. The condition of having a unibrow is synophrys.-Beauty culture:...

, a wheezy

Wheeze

A wheeze is a continuous, coarse, whistling sound produced in the respiratory airways during breathing. For wheezes to occur, some part of the respiratory tree must be narrowed or obstructed, or airflow velocity within the respiratory tree must be heightened...

 voice, and gleaming eyes. He is often distinguished by the V.F.D. insignia tattooed on his left ankle (as with most V.F.D. members

V.F.D. members

In the children's novel series A Series of Unfortunate Events by Lemony Snicket, many characters are members of a secret organization known as V.F.D. The following is a list all of the known members of V.F.D.-Beatrice Baudelaire:...

).

Following the death of Bertrand and Beatrice, the Baudelaire orphans are placed under his care, and he proves to be a horrible guardian, only interested in the fortune left behind by their parents.