Unlike the other major characters in the novel, Marius grows up in a well-to-do household free of financial worries. Nonetheless, his family is split apart by politics, and it is not until he develops his own personality that he is able to become whole. Marius’s loyalties are torn between his father, Georges Pontmercy, who is a colonel in the Napoléonic army, and his staunchly monarchist grandfather, M. Gillenormand, who raises him. The political differences between his father and grandfather threaten to tear apart Marius’s identity, as he learns that his conservative grandfather intentionally prevented him from establishing a relationship with his father out of fear that Marius would succumb to his father’s liberal political views. Angry and confused, Marius adopts his father’s beliefs, but it soon becomes apparent that what he really needs is an idealism of his own. Marius begins to develop truly only when he leaves Gillenormand’s house, finding himself and falling in love for the first time.
Marius is more innocent than the other characters in the novel, and while this innocence keeps him from becoming cruel or cynical, it also makes him occasionally blind to the problems of others. This lack of perception first becomes clear in Marius’s treatment of Eponine, and becomes especially unattractive when Marius drives Valjean from his house. In the end, Marius is a good person, but his inability to perceive the needs or feeling of others can at times make him unwittingly malicious.