How does Lucillius, a minor character in the play, help advance the plot in this passage? Lucillius is protective of cassius so he diminishes the seriousness of the conflict. Lucillius tells brutus that cassius intends to attack brutus, increasing the tension and conflict. Lucillius does not tell brutus much about cassius, which causes brutus to question the loyalty of lucillius. Lucillius explains that cassius is far less frlendly than he once was, and brutus uses the information to confirm his judgement that cassius is turning against him.