My Take on the Ninja Turtles
Leonardo
Weapons: Katanas, throwing stars, knives, and anything else he can get his hands on.
Color: Red at first, mainly blue
Role in the family: Protect everyone else, no matter the cost to himself
Hobbies: None, unless you think practicing and studying qualify. It has been hinted that he reads stacks of comics.
Other Information: Supposedly hates guns, is honor-driven, and knows enough to stay away from Donatello's computers and Splinter when he's pissed at another turtle.
Everyone else, it seems, likes to think of Leonardo as a bossy, over-protective "big brother" who'd bend over backward for Splinter and'll go insane when the master dies. I think this is how his brothers might see him, but then I believe his siblings are just like other siblings, self-absorbed and possessed of a kind of familial myopia. I'm not saying that they are egotistical and selfish, (well, I'll get back to Raph later), but they do seem to occupy their free time with things they want to do. Donatello has his computers and spiritual studies, Mike has his writing and/or socializing., and Raphael takes off at night to do his brooding and sulking. Even Splinter has his meditation. Leonardo practices.
That's where his free time goes, into endless katas, advanced weapons practice, mental exercises...and if he's not awake studying, the general consensus seems to be that he sleeps on the couch. Paranoia? Maybe. But consider his past. He's suffered whenever he's lost control and became careless and emotional. Christmas Eve. The roof in the first movie (if you want to think about those movies). When you're responsible for the welfare of your family and you've seen that your emotions can put them in danger, you grow cold. Fast. I believe he even has problems showing his emotions when his family isn't in danger. Of course, you never know what might happen in the next minute, so he has to always be on guard, which could be leading him straight to a nervous breakdown. This pressure would be the only thing that would drive him to suicide, unless of course his family was killed.
But where does this responsibility come from? Why the all-consuming obsession with protecting his family? Why didn't someone else, Raph maybe, get the burden? Simple. Splinter. He chose the one he thought would be the best able to fill the role. The master may give his other sons occasional words of advice or guidance, but he doesn't have long conversations with them, doesn't take the time to lecture them as often as he does with Leonardo. This is not to say that he doesn't love them, but he's chosen his main student and that's who gets all the attention. Whether or not this is good for Leonardo is definitely uncertain. Eldest children and "only-children" will understand.
Eldest children must be a role-model, intelligent, rational and sensible for their younger brothers and sisters, at least that's what the parents, society and social stereotypes say. They must be honest, responsible, capable of handling situations. They must shoulder much of the load of watching and helping the rest of the family. And their problems? They have no one to turn to, except maybe a few friends. They need to be able to take care of themselves, especially since the parents have to look after the younger children. And remember, Leonardo has no friends. An extended family, yes, but no friends. Who does he turn to when he's hurt? He obviously hates leaning on other people. Splinter? Wonderful, another lecture on what he's doing wrong and what he should do. Leonardo is also very much an only child in that he's alone, spiritually and physically. Yes, he lives in a crowded underground apartment, but does he ever join his brothers in their hobbies? He apparently doesn't like or trust computers, he's not as social as Mike, and Raphael...I think there's a jealous envy there, but more on that later.
Leo practices mostly alone, keeps to himself and keeps all of his emotions bottled. An only-child learns to keep his mouth shut so as not to draw anymore suffocating attention to himself, to hide any activities unfit for the parent's eye. These actions don't have to be perverted or illegal, just unapproved. Can you see Leo reading comics with Splinter? Not gonna happen. What few actions are accepted and expected are presented freely. What is not, is hidden. Leonardo is, for all intents and purposes, trapped in his role, practically held prisoner by his master's expectations. Hence his jealousy of Raphael.
Raphael may be just as skilled as Leonardo, except he's probably a bit less comfortable or fluid with the motions since he hasn't had the ungodly number of hours of practice Leo performs. He goes wherever he wants, does whatever he wants (for the most part) and doesn't have to hide his emotions. Raphael is like the second prince of the kingdom--all the privileges with a minimum of responsibility. The first son is heir apparent. The second son is the backup, with greater freedoms and liberties. It could be, however, that Raphael really craves Splinter's attention and "acts up" for it, which is ironic in that I think Leo doesn't want that attention. If Raphael could see past his own desires and actually observe the relationship between Leo and Splinter, he might see that, but instead he is consumed entirely with his own wants, needs and desires.
Leonardo must feel a kind of angry jealous since Raphael can do whatever he wants, and instead he seems to waste this freedom. He had a girlfriend, but that never does work out for him, either with Ninjara or Lucindra. He loses his chances with women. Leonardo never had much of a chance to be with anyone, except Lotus (remember her?). Is it likely Splinter would approve of a relationship between his star pupil and a thief? Yes, Ninjara was a thief, but she was a moral thief. Lotus made it clear she was out for gold.
As a side note, there have been many females Leonardo has been around, but only one girl came close to his heart and that was Lotus, and it is interesting to note that she is one of the few (very, very few) women who have defeated him. This makes me suspect that he can only respect a girl who can trounce him, which would make for an unusual sex life. I have a feeling that if Leo and Lotus got together, she would call most of the shots. Why would Leo want too much responsibility? He already has that now and probably doesn't like it. I think he'd like for someone else to take the reins and let him sit back a little bit.
I would even go so far as to say if Splinter died soon, Leonardo would not go insane, depressed, or suicidal. Rather, I think he'd see it as a relief, and once the shock was over and he was sure his family would be all right, he'd leave and finally live for himself, for the first time in twenty years.
And another thing: everyone also likes to say that he hates guns. It's never really explained why. Is it because they make killing easier? Faster? Less personal? This is a catch-22 argument. Of course, if he doesn't like guns, then why does he like throwing stars, or arrows, or throwing knives? Why not all other projectile weapons? But we see him using these weapons, so it must be guns in particular.
If he doesn't like guns, then it has to be for a reason, and since we haven't seen any of his friends or family die by one, we can assume it is for reasons of honor. Guns make killing too easy. But if it is the ease of killing that he hates, that means he prefers professional warriors and soldiers (i.e. combatants) in a fight. No innocents, kinda like the Predator in that Schwarzennegger movie. And if that's true, wouldn't he see himself as a professional warrior? An efficient fighter and killer? That's dangerously close to be considered psychopathic. It means Leo's a cold-blooded honor-driven fighter with lethal combat skills and a brutal code of ethics. In other words, here's someone you wouldn't want to meet in an alley late at night.
Of course, maybe he doesn't really hate guns. I know, this supposedly runs cross his character, but he is a ninja, after all. Not a samurai. His sword does not hold his soul. His type of honor is different from traditional Japanese Bushido. In fact, he does not practice Bushido, save for one tenet of fealty to his master and family, and just about everyone has a loyalty to their family. I see Leonardo more as lone figure, fighting to keep the people he cares about safe and sound. For example, would he insist that one of his brothers commit suicide if they committed a major blunder? No way. I think he's almost neurotic about taking care of them, and would do anything necessary to that end. If an M-16 was all he had to keep a horde of enemies from one of his siblings, do you think he would even hesitate to use it?
I don't think he would believe in Buddhism, either, since he seems to need proof on things, more so than even Donatello sometimes. He wants to check everything out, make sure it's all right for his brothers, interrogate every new face they meet. Blind faith just doesn't seem to fit him. Plus, Buddhism is a little non-violent for him. Yes, there are Buddhist warrior monks, or at least we see them in every Hollywood martial arts flick, but they seem to be mostly defensive fighters. Leo just comes across as someone who would actively seek and destroy the enemy, and really wouldn't hesitate to use deadly force if it was required. He's the most consummate fighter in the family, and is even more dangerous in that he thinks and plans ahead.
If he did go insane, for any reason, he'd be nearly impossible to take out, and in fact, I think his worst fear should not be snakes (that is the dumbest thing I ever saw on that show, aside from the talking brain), but rather, he would be afraid that he would do something to hurt his family. If he thought he had become a danger, that would be the only reason he would commit suicide.
Future Projection: I predict that in the future, Leonardo would be out on his own with little contact with his family. Splinter would be dead, freeing him from any familial obligations, and once he knew his brothers were relatively all right, he would take off, presumably with Lotus. Most likely he would become an assassin, mercenary or thief, seeing as those are his greatest skills. To his credit, I don't think he would pick on innocent people or kill anyone he didn't think deserved it. He would probably turn into a kind of deadly Robin Hood, killing evil people, setting fires and stealing just about anything, and cutting a check from it at the same time. Splinter really raised a great criminal mastermind, didn't he?