Two Minor characters that greatly affect Hamlet in this play are Laertes and "Rosencrantz and Guildenstern". Hamlet acts different when he is around them and develops into the ruthless person he has to be if he wishes to kill Claudius and take the crown that is rightfully his. Rosencrantz and Guildenstern begin the process of making him more ruthless by causing him to begin lying to people and start to deceive people into thinking he is crazy. When he fights Laertes he is at last ready to take charge of the situation.
First Rosencrantz and Guildenstern, they help start Hamlet on the path to revenge for his fathers death. They are some of the first people he really gets mad at and actually goes off on. He says to them, "Why, look you now, how unworthy a thing you make of me! You would play upon me, you would seem to know my stops, you would pluck out of the heart of mystery, you would sound me from my lowest note to the top of my compass (Act3 Scene2 Lines 393-397)" In this scene he lets them know he was on to them the whole time and that he was using them to play with his uncle/stepfather and not the other way around. In this scene he is finally confronting someone instead of just planning and scheming. This is a necessary step in order for him to be able to kill Claudius.
Second, Laertes, at the point when he and Hamlet fight, Hamlet has finally gathered up the courage to act on what he feels. He has stopped hiding in the background and is even willing to fight Laertes in a wager. Here the play will come to an end. Hamlet fights well, and after he has scored a couple of points against Laertes, they begin to fight for real after Hamlet is cut on the shoulder by Laertes" sword. He then proceeds to kill Claudius. At this point Laertes has brought out the fighter in Hamlet. Before now he had not stood up to anyone in a physical manner aside from the death of Polonius which was an accident to begin with.