Marius first appears when he and his friends of teh ABC decide to revolt against the soldiers of France for what they are doing to the poor. He runs into Eponine and asks her what's going on, but Eponine refuses to tell, but unknown to Marius, she has a secret crush on him. Marius then sees Cosette and falls in love with her and she with him. Marius arrives at the cafe where his buddies including Enjolras and Granitere tease him about his new found behavior. They then hear from Gaveroche that General Lamarque, the only person in government who shows sympathy for the poor has died and they prepare to fight for war. With a sad Eponine's help, Marius finds Cosette and they affirm their love for one another. When Marius hears that Cosette has to move because her adoptive father, Jean Valjean is on the run from Inspector Javert who has been chasing him since the day he broke parole. Marius decides to go to war. Marius then fights the battle and almost is killed until Eponine disguised as a boy takes the shot for him, thus revealing herself as a girl to the revolutionaries and had stolen Cosette's letter for Marius earlier in which she gave to him. She apologizes and then dies. Marius writes a letter to Cosette in which he turns to Gaveroche(Eponine's estranged brother) to deliver it. He meets Jean Valjean who joins the war as a volunteer. On the barricade's last night, Marius falls asleep while Valjean prays for his safety. While they fight the last fight the next morning, everyone dies except Marius who fell unconcious. Valjean carries Marius through the sewers and out to his home where he is cleaned up and reunited with Cosette and his grandfather. Marius mourns for his friends who died at the barricades, but Cosette comforts him and tells him that they'll be together forever. Marius learns of Valjean's past, but begs Valjean to stay with them. Valjean makes Marius promise not to tell Cosette and Marius agrees. Marius and Cosette get married soon after. He is confronted by the Thenardiers who show him the ring they stole and told him that Jean Valjean had murdered someone. Reconizing the ring, he realizes that Valjean saved his life at the barricades and he and Cosette leave just in time to find Valjean and thank him for saving his life before he dies. He later comforts Cosette over the loss of her adoptive convict father.
In "MCF and the Crusades" and "MCF: The Musical Adventure", his role is the same, but he gets help but not only Valjean, but from Cedric, Raina, Tracy and Seamus(though one of the former in the other appearence).
- Marius is simular to the Prince in Cinderella, how they both fall in love with teh commoner girl and care for her no matter what. They marry at the end as well.
- Nick Jonas played Marius in teh 25th anniversary concert edition of Les Miserables.
- In the 2012 movie and book, he had a grandfather who is disappointed with his choice of going to war, but acceptful once he brings his love Cosette home after she takes care of him.
- MCF and the Crusades(debut)
- MCF: The Musical Adventure(upcoming)