The story of how the character of Maximus developed is an interesting one. As the directors and the story crew spent time developing the characters, we knew right away that Rapunzel's male counterpart would be a dashing thief, with the local law pursuing him relentlessly for a major theft he just committed. We didn't just want him to always say "I'm in trouble and the authorities are after me", but we wanted a physical embodiment of that pressure so that we could visually show that he was being stalked by the law relentlessly. The first impulse we had was, of course, the most obvious: some determined Captain-of-the-Guard type, a tough soldier that would pursue him with unceasing vigilance.
But since that was our first idea, we knew it was the most obvious and expected. So we challenged ourselves to do better and quickly came up with the idea that the Captain of the Guard's horse should be the most determined and resourceful "soldier" in the whole army.
Like all characters, he took a few passes for us board artists to push his abilities to their fullest extent, to figure out what was possible for him to do, what was funny for him to do and what feel flat and didn't work for him.
The turning point was one day when someone on the story crew said "he should be like Tommy Lee Jones in 'The Fugitive'", and we all laughed at that way of putting it. After that, his character was completely clear to me and I knew just how to draw him and what he should move like and what his expressions and body language should look like. He's a very serious guy who doesn't suffer fools well, and he literally doesn't care that he was born a horse - being an equine is inconsequential to him because no matter what animal he was born as, Law and Order are his obsessions, and he would rather die than let someone get away with any crime, no matter how small. I'm not sure of he sleeps, but if he does, he definitely keeps one eye open.
Robert McKee calls it a "comic obsession": a singular goal that consumes a character completely. Characters who are your main players and have to carry the emotional weight of the film have to have depth and layers and several facets to their personality, so that they can be interesting enough for us to follow and also so they can seem like real people with depth so that they can grow and change by the end of the film, which is where the emotional swing of any movie comes from. But the supporting players can be one-dimensional, completely obsessed with a goal or ideal and pursue it with a single-mindedness that is fun to watch.
And even though your main characters need to have depth and breadth so that they can have emotional growth during your movie, in any comedy they should always have their own humorous slant as well, so that the movie doesn't feel like the main characters are dull and serious while the sidekicks have to be wacky comedy relief. That's an awkward and uninteresting combination and make it feel like your characters all belong in different movies. I love The Dude in "The Big Lebowski", and how his "comic obsession" to replace his ruined rug drives the whole story. But he has to go through a lot of other emotions in the story and has other things to deal with besides just the rug...so he can't only be about getting his rug replaced. But other characters in the film who aren't the main character and don't have to carry as much story weight get to have their own levels of "comic obsession": Walter, Jesus, Mr. Lebowski, Maude and all the rest get to have great "comic obsessions" that make them fun parts of the ensemble, but they wouldn't be able to go through all the experiences and troubles that the Dude has to go through, because they simply don't have the depth and range of emotion.