Duke Orsino explained
Who is Duke Orsino
Duke Orsino is not a main character but he plays a big role in the Shakespearean play and the Movie. In the play and the movie, Duke is in la la love with a girl named Olivia, so he asks Viola, playing as Sebastian, to get Olivia to like him or keep him in interest.
Duke Orsino is a male character. As males, there are times at the beginning where you don't know that the girl likes you or that you want help to get the girl to help you. In the play, He goes and asks Sebastion to ask Olivia to talk to him.
In the play, they see Duke as a person that's completely head over heels for Olivia.