Impulsive Passionate Intelligent
Claudio has previous knowledge of Hero's personality since he met her before the war; when Claudio returns from war, since he is so impulsive, he immediately asks the same night to be married to hero. However, Claudio is appalled When Don John deceives him into thinking that Hero would have an affair. The next day at the wedding, he expresses his angst that he built up the night before by publicly insulting Hero before the entire town, and when he does so, he demonstrates how passionate and assured he is about his opinions. However, he is also Intelligent; he makes sure to verify any event that happens according to his memory. If any intelligent person is deceived along with another witness, the deception can be very powerful. As the primary antagonist, Don John is very smart, and he knows that his plan will work in this specific scenario. However, since the play is a comedy, we know that Claudio will get married to someone. If Claudio wasn't a morally-driven and intelligent person, he would have never made the decision to agree with Leonato About marrying the "niece".
Claudio Causes some conflict that the plot leverages in order to create an emotional reaction from the audience that creates biased opinions about Claudio. I think that the way that he suddenly changes his thoughts when he is told that hero died clarifies the fact that he is very honest and morally-driven.