Hateful, Spiteful, Disdainful
Don John is motivated to cause pain to others because of his general negative outlook on life caused by his low social class and lack of acceptance by others. "I had rather be a canker in a hedge than a rose in his grace, and it better fits my blood to be disdained of all" This shows that Don John believes that he is not only prevented from being accepted because of his bastardy, but he would also not desire this acceptance should it be offered to him. Don John wants nothing more than to displease and anger those who have devalued him because of his illegitimacy as the prince's brother.
Don John is the illegitamate bastard brother of Don Pedro, the current standing prince. His illigitamacy as a noble's son prevents him from any privilages that would be carried should he be born to his father's wife rather than out of wedlock. He is a younger man present in Don Pedro's group of soldiers. He seems to have the loyalty of several of the soldiers, who do his bidding, such as Borrachio who willingly destroyes Claudio's desire for Hero on Don John's whim. While Don Pedro claims to care for John while he is in his presence, John remains a hateful person. He holds disdain over people in relation to how they look down on him for being a bastard, and often reminds those who speak with him that he is only in the cavalry because he is the prince's half brother and he is not actually cared for nor trusted. " I am trusted with a muzzle and enfranchised with a clog; therefore I have decreed not to sing in my cage. If I had my mouth, I would bite; if I had my liberty, I would do my liking" This shows that he would also confront his oppressors should he have the opportunity, which relates to his actions against Claudio and Hero and his desire to cause pain to those who act merrily in his presence. Don John is a static character, and throughout the entirety of the story he never changes, he remains the hatefull illegitimate he started as.
Don John is a vital part of the plot, and he represents obstacles of love and the unfairness of life in relation to the theme. Don John was born as the illegitimate son of Don Pedro's father. This bastardy set him apart from all others, and he was given less regard, attention and caring. This relates to the plot of love by showing that Don John has absolutely none, unlike characters like Benedick who harbor their love in secret, Don John has never loved or been loved. "it better fits my blood to be disdained of all than to fashion a carriage to rob love from any" Because of this his only pleasure is meddling in the affairs of those who have unfairly devalued him. Should John have not existed, the play would end about ten minutes in. His tricking of Claudio into thinking that Hero has not only failed to remain a virgin, but was unfaithful to him creates the entire conflict of the play. John himself has no apparent "love" but he is present in the attempted destruction of Hero and Claudio's which represents him as an obstacle.