Martin Brisby is a brash and bold young mouse, the oldest son of Jonathan Brisby and Mrs. Brisby.  Since his father's death, Martin has worked hard to assume the "man of the house" (mouse of the house?) role for the family.  But his impulsiveness and youthful bravado keep getting in the way.  Still, he's got a good heart, and cares very deeply for his mother and his siblings...though he's not too terribly fond of, or patient with, Auntie Shrew!

QUOTE: "I'm not afraid of the dark...I'm not afraid of the farmer...I'm not even scared of Dragon!  I'm not even afraid of...of...of the Great Owl!"

Origins of the character: In Robert C. O'Brien's book "Mrs. Frisby And The Rats Of NIMH", Martin is rather different than he is in the movies.  He's described as "the biggest, a strong, quick mouse, dark-haired and handsome like his poor father."  Martin does not display any of the brash and impulsive nature he has in the first movie, nor the emotionally-conflicted nature he has in the sequel.

In the animated sequel: A few years along and, as the action in the movie opens, Martin is a bit older (approximately the equivalent of 12 human years), and a bit more sensible.  However, he's also frustrated and emotionally-conflicted, as he has been told that, even as the oldest son of Jonathan Brisby, he's not going to be the one to go to Thorn Valley to be a hero-in-training and fulfill a prophecy, but that it will be his younger brother Timothy.  Martin is rather bitter about this and, while he loves and looks after his brother, he's nursing a grudge.  He also goes through a bit of a change in the sequel--his eyes go from brown to green, and his fur from light brown to light gray.  He changes substantially into an evil character during the movie (for which there is a separate entry in the character list), but at the end the rats of NIMH, and Mr. Ages, manage to restore him to his old self, though now a bit older (approximately 19 human years).