"Alas, thou hast misconstrued every thing." If earlier scenes were about misuse and misinterpretation of language, this is a scene about miscommunication. Cassius dies because Pindarus misreads the battle and Cassius despairs — a despair that began in Scene 1. Cassius grasps at Pindarus' words as justification for what he desires: death. Titinius and Messala believe that Cassius killed himself because he lost faith in the rightness of their cause and in Brutus' abilities. This interpretation of his death will be all the more hurtful to Brutus.
What is interesting to note is the way in which the audience's views of these two characters has changed since the beginning of the play. Cassius was a dark manipulator of language. His motives for killing Caesar were murky — the readers knew there was more to Cassius' intentions than he admitted. He was emotionless, clinical, and detached; not a friend to Brutus, but a suitor of his power and reputation. At the end, Cassius is prepared to show his great love for his friend and, although this love is noble in itself, it diminishes him to some degree. Note that Cassius' melancholy is the "mother" to his death. In contrast to Brutus' virility in the face of his great friend's death, Cassius is less manly.
Brutus, who at the beginning of the play was passive and pursued by Cassius, is now a man of action. In addition, any doubts that the audience may have had about Brutus' nobility are swept aside by the sympathy gained for him through the powerful friendship he has developed with Cassius.
