Marcello, son of Pina, represents the new generation.
He is a young fighter, fearless, ready to die for freedom
Children are perhaps the least realistic characters in the whole movie.
It seems that their childhood has disappeared with the war, to give space to an idealized image of the new man, who as a child is already an adult.
They do not fear death when they decide to blow up a truck of the German troops with explosives … they fear perhaps more the punishment from the parents but they also face this as real fighters, because they are not playing the war, as they think their parents, they are really fighting in that war.
They face death by attending the shooting of Don Pietro, They are there to give him courage with their presence, and the death of their parish priest does not cause in their terror but a renewed strength.
in the final scene, we see them return to Rome, to the capital, sad for the loss of their Shepperd but ready to start the fight again, ready to build a new world based on the values of Justice and Freedom and Faith (final images focused on St. Peter)