What is Shakespeare’s larger purpose in his characterisation of Coriolanus in Act I?

Coriolanus is a very interesting character in the sense that he very much follows the "classical hero", yet later on in the play is able to be portrayed as a "villain". It is important to remember that this is a political play. Shakespeare takes a decently clear stance at his main character in the first act, establishing him on two fronts; the battleground, and the city and capitol building. Depending on where the scene takes place, we, the audience, get a clear understanding about his character and how he reacts and deals with certain situations he must face.

The first bit of information the reader receives about him is his unfairness towards the commoners and citizens. He steps out and it is easily recognisable that he does not completely know how to deal with the situation at hand. He is arrogant and angered easily. With further development of Act 1, the audience sees him fighting in battle. At this point, clear indications of his character protrude. He is a fierce and brave fighter. He motivates all his comrades in battle and is willing to do anything for victory. It appears that he is nearly unstoppable, which can be identified by his many battle wounds, yet still taking down enemies and coming out victorious.

On the other hand, the reader comes across Coriolanus's other self in the city. The communicational problems between Marcius and the civilians are extend and are more easily noticed. The reader comes to terms that he is fairly incapable of coming to terms with the citizens. Going into rage fits fairly often, the readers are introduced to the main conflict of the play.

Coriolanus being unable to come to terms with the civilians makes himself the enemy of the city. The people feel unfairly treated, and he quite frankly could not care any less. This causes him to be the enemy in the public eye, even though he is the hero on the battle field.