Giovanni is just a kid—also another one of the good guys. The son of Brachiano and Isabella, and successor as Duke after Brachiano dies, he doesn't get too many lines—but the lines he does get are important. He wonders poignantly about the afterlife and his mother's death (3.2), warns Flamineo to "study your prayers" (5.4), and speaks the last lines in the play, after arresting Lodovico:
Remove these bodies. See, my honour'd lord,
What use you ought make of their punishment.
Let guilty men remember, their black deeds
Do lean on crutches made of slender reeds. (5.6)