Who is the hero of Kidnapped?

Kidnapped is an adventure novel by Robert Louis Stevenson, published in 1886. The term hero, when applied in a literary context, refers to the protagonist or main character of a narrative. In this sense, the hero of Kidnapped is David Balfour. It is David's story that the novel follows, from the death of his father, his journey to Scotland to find his uncle, and his sale into slavery by that villainous relative with the ensuing adventures. David's quest for his proper place in his family and for justice against his scheming uncle drive the plot of the tale toward its ultimate resolution. David Balfour also meets the criteria for a hero because he is brave and loyal, earning readers's sympathy as a person of integrity.
The non-literary definition of hero is one who displays admirable or noble qualities. In this book, this meaning applies not only to David Balfour, but also to other characters who provide David with indispensable aid. Alan Breck Stewart, although wanted by the crown of England for treason, is a faithful companion to David for most of the book. When David is weak from the strains of their flight, Alan helps him survive. He could therefore be considered a hero in the book. Alan helps David find Mr. Rankeillor, the family lawyer. Mr. Rankeillor helps David persuade his uncle to share the inheritance with him. Because of his work to secure justice for David, Mr. Rankeillor is a hero in the general sense of the word.
https://literarydevices.net/hero/