Diomedes is a Greek leader with few illusions about how the world works.
Absolutely without any form of idealism, he thinks that Helen has cost far too much blood on both sides and that she cannot be considered worth it. Though he takes some care to seduce Cressida, this is simply because it is the best way to get her into bed other than raping her. He has no respect for Paris, Troilus or Menelaus, and has no qualms about expressing his lack of regard for them, or his extremely poor opinion of Helen. He is a dangerous fighter, and not a particularly nice man. He forces Cressida to give him Troilus’s love-token of a sleeve and wears it in his helmet during the battle as a dare to Cressida’s former lover.