Casca is a cynical Roman with no great taste for Caesar’s fooling over the crown.
He disdains the mob and their poor oral hygiene as much as he disdains Cicero’s elitist erudition. His poise is shattered by the storm and eerie events of the night, and in that state is convinced by Cassius of the need for Caesar’s death. He agrees with the need to have Brutus on board for the sake of convincing the people of the justness of their cause. He at first wants Cicero to be asked to join as well, but Brutus quickly convinces him otherwise. He is the first to strike Caesar at the Capitol.