Count Olaf is the main antagonist of Lemony Snicket's A Series of Unfortunate Events novel series and its 2004 film adaptation. Count Olaf is greedy and will go any lengths to get what he wants, even if it involves murder. He appears in every book of the Series of Unfortunate Events, in some form or another. He is also the archenemy of Violet, Klaus and Sunny Baudelaire.

Klaus Baudelaire is the middle sibling of the Baudelaire Orphans and the deuteragonist in the thirteen book series A Series of Unfortunate Events. He is the brother of Violet and Sunny Baudelaire. He is an advent reader, and can dutifully remember what he's read at any moment.

She is the youngest of the siblings. She loves to bite things with her four teeth and despite being a baby, is very smart. She is one of the three main characters of Lemony Snicket's A Series of Unfortunate Events series who appears in all thirteen novels. She speaks in all gibberish with (translation here)

Violet Baudelaire is the eldest of the three Baudelaire orphans and one of the main protagonists of A Series of Unfortunate Events. She is the daughter of Beatrice and Bertrand Baudelaire as well as the elder sister of Klaus Baudelaire and Sunny Baudelaire. She’s an inventor, her brother Klaus is a good reader and, her little sister Sunny likes to bite stuff.