(quite possibly the only one of its kind in the world!)
There are spoilers here, although none of them are extreme--I don't think any of them would prevent people who still haven't read the story from enjoying it, but your mileage may vary, so you are warned now.
When we first meet Mitaka, everything suggests that he's going to be a total jerk. He's rich, he's handsome, his teeth sparkle in the sunlight, he's got a suave, polished manner, and a reputation as a ladykiller; which may or may not be true, considering how often the tennis club's gossip is on target, but we do not learn about that until later.
So the surprise is that, in a subtle twist, he turns out not to be a jerk (or, at least, not a total one!). After planting all these obvious clues to his "jerkiness", Takahashi very skillfully spends the next few years portraying Mitaka as a rather different sort of person. In his interaction with Kyoko he shows sensitivity and a genuine interest. In his interaction with Kyoko's very obnoxious tenants--especially Mrs. Ichinose, who continually creates awkward situations for him, and Akemi, who's all over him from the get-go--he shows a characteristic, graceful self-restraint which he carries on for years and years. And even though he needles Godai from time to time--after all, Godai is a rival, and Mitaka's personal code clearly allows for some kind of psychological warfare--he never berates him in his conversations with Kyoko; he is openly friendly to him, fixing a bowl of soup for him when he finds him lying sick in his apartment, visiting him at the hospital when he breaks his leg, getting drunk with him in a strange episode of male bonding, and inquiring about his job prospects in what seems like a genuinely concerned tone.
One might think simply that he is a hypocrite: he wants Kyoko, so he feels he has to humor her friends and acquaintances and put up with their antics. There is no question that he generally acts out of self-interest: for instance, in the episode where he lets Kozue confide in him and tries to give her some sentimental advice, there are, of course, obvious reasons why he would like to see her relationship with Godai move forward; but still, in that episode as in all the others, his kindness is genuine, whatever the ultimate motive for his actions may be. We never see any thought balloons or facial gestures to indicate that he actually despises all these idiots that he's putting up with. He doesn't. These are people, and being nice to other people is an essential part of Mitaka's nature.
Mitaka's uncle, who is of a very different nature altogether, does count on his nephew's good heart and sense of duty to further his own schemes, and, as it turns out, he's basically right in his assessment of Shun. The main reason why Shun does not break up with Asuna earlier than he does (or tries to) is because he does not want to hurt her. It is significant, I think, that when he finally works up the nerve to dump her, it's only because he has convinced himself that it is his duty to rescue Kyoko from poverty. He needs to feel that he is acting out of an altruistic motive, in order to justify to himself the pain that he is going to cause.
This is not to say, of course, that Mitaka is perfect; even before he starts acting like a total cad at the end of the series, we get at least one troubling glimpse, in the hospital scene with Kyoko, that he may have a bit of a manipulative streak in him. This makes it a little hard to take at face value Kyoko's assessment of him a year later, when she seriously contemplates his offer of marriage. (It is also unclear what to make of the testimony of Asuna's dogs, for that matter.) And yet, even at the end of the series, after Mitaka has given Kyoko plenty of reasons to dislike him, she holds on to her belief in his fundamentally decent nature, and she tells him so. Clearly, I believe that Kyoko is basically right about this.
Shun's reputation as a ladykiller precedes him, but what we actually see of his exploits in this field is again very different from what we might otherwise be led to believe. He is extremely respectful with Kyoko, for instance. The very first time he tries to kiss her, after months of friendly dating, we can see him struggle with the decision, not at all as a professional seducer or man of the world would, but as a nice guy who is really in love. His remarks to Kozue about "being just friends" versus actual romantic involvement also seem typical of a nice, almost shy person, who'd rather relate to women as friends than as objects of lust.
Regarding which, there is also the remarkable statement he makes to Godai, when they are drinking together, about the coterie of girls who visit him in the hospital: "I just went out with those girls, I didn't do anything with them". There is really no reason to believe he's feeding Godai a line, since the only person for whose benefit he could possibly be saying that would be Kyoko, and there is no way he can think that Godai is going to tell Kyoko.
Finally, the scene where Mitaka takes Kyoko in his arms at the hospital and feels her resistance weakening shows some evidence for both the "good Mitaka" and the "bad Mitaka" viewpoints. On the one hand, he seems entirely too cold and calculating in the way he tries to manipulate her feelings to get her away from Godai. On the other hand, he also decides not to press his advantage, because "forcing it is not his way". No doubt he regrets this decision later, in his darkest hour; but at that moment it is a reflection, both of his basic decency, and of the very idealistic nature of his love for Kyoko. Mitaka does not really want to take advantage of her, then or at any other time; he only wants to cancel out Godai's recent gains, to restore (a semblance of) an even playing field where he will, once again, have a fair chance to win her heart. He probably justifies his actions to himself by thinking that Godai has had, up to that point, an unfair advantage, by having Kyoko nursing him alone for several days: an excellent chance to develop the kind of intimacy which, in fact, does develop between them.
Through it all, what Mitaka wants is not a momentary thrill, but Kyoko's heart, freely given, not snatched away in a moment of passion. It is for this that he waits, ultimately in vain, for five long years; and he will say goodbye to her without having once kissed her lips.
Clearly, from all the above, Mitaka is big into self-restraint and self-discipline. He gives Godai once a bit of a lecture about this: "normal people experience personal and spiritual growth through suffering..." Ironically, the words he speaks to Godai on this occasion will come back to haunt him before the end of the series. But there is no question that Mitaka believes strongly in this somewhat stoic philosophy, which I'd trace back to the Confucianism that has historically shaped much of the Japanese mind.
Mitaka's greatest accomplishment in this regard is the way he eventually conquers his mortal fear of dogs. He goes as far as to boast about it, something he doesn't normally do, and he may have good reason to boast. But it is interesting that he tells about it to his uncle using an analogy with the training of ninjas, whereby he makes it explicit the connection he feels between himself, his personal code, and the old "warrior ways" of Japan.
Self-discipline, honor, sense of duty: these traditional Japanese virtues are overlayed, so to speak, on top of Mitaka's fundamentally kind nature; joined to the more questionable qualities of a certain ambition and more than a bit of pride, they give his personality its sharper, more aggressive edge. I suspect that the result is as close as possible to the traditional Japanese masculine ideal. If so, it is interesting how Kyoko ultimately rejects this traditional ideal, choosing instead the much more pathetic Godai--a failure, or pretty close to one, by most conventional standards. It may reflect the fact that Kyoko has never quite seen herself to fit the standards that they--her parents, her society--would like to hold her up to. It is clear, for instance, that Mitaka feels much more duty bound to abide by the wishes and desires of his family than Kyoko ever would.
How much of Takahashi is there in Kyoko? I have no idea, but I once suspected, after reading the episode where Mitaka says his final farewell to Kyoko, that this was based on real life; that Takahashi had been there, with a real-life Mitaka, before. I have no proof of this, of course, and even if it were true who knows how much Mitaka's character could owe to his hypothetical real-life counterpart.
It also seems clear to me that Takahashi relishes the incredibly outrageous nature of Mitaka's trials and tribulations, especially at the end of the story, and heaps indignity upon indignity upon him, in part at least, just because he is such a stiff, self-possessed character. He is just too good a straight man for her irrepressible nature. And yet, however amused she may be by him, she is also genuinely fond of him. One can feel her wishing him well in the last episode, with all her heart.
The truth is, however, that Mitaka, for all his talk about hardship as an occasion for personal growth, has not really had to overcome a lot of hardship in his life. His family is well-off, and he presumably has had all the advantages that money can buy. He may have had to work hard to become a good tennis player, but once there he had it pretty much made; by his own admission he did not even start to look for a job until after he graduated from college.
Considering all this, one has to say that Mitaka has actually turned out remarkably well, and this is even more true when one examines the character of his relatives. His uncle, the father's brother, is a ruthless manipulator; his parents are both charming and incredibly shallow. The father, in fact, looks to me a little like Ronald Reagan, and, considering that he was introduced in 1986, I suspect this is not a coincidence (if it's deliberate, I wonder if this is as close to political commentary as Takahashi has ever gotten). The parents, however, are kind people, in their very superficial way, and it is clear that Mitaka has inherited this trait from them. He has also, thank heaven, a lot more depth to back it up with.
But Mitaka also has the manipulative streak mentioned earlier, if not quite nearly as strong or as ruthless as his uncle; and his natural kindness has never been harshly tested by circumstances. For Takahashi, who cannot let an occasion for irony go by, Mitaka's casual words to Godai, "...or are you the type who grows more twisted in his misery?" are going to be the key challenge for Mitaka to face at the end of the series. He does not do too well at first.
Heroism has been defined as grace under pressure, which suggests that this is a rare quality. Just how rare, I guess, depends on the pressure; but there is no question that Mitaka does crack under the extreme pressure he experiences at the series' end. Desperate because he feels Kyoko more and more slipping away, Mitaka crosses, one by one, all the lines he had drawn for himself up to that time. He lashes out verbally at Godai; he breaks up (or so he thinks, anyway) with Asuna; he launches an all-out attack on Kyoko, and is rather less than candid, if not actually deceitful, in the scene at the gravesite, where he does not disclose that he has been eavesdropping behind the bushes. It is there also that he conceives the notion of trying to do to Kyoko what his uncle has been doing to him: namely, to have her family put pressure on her to marry him. This may be, morally, Mitaka's lowest point, but the tale of his decline isn't quite over yet.
There follows the scene at the restaurant and the clumsy seduction attempt at the hotel, with Mitaka all set to break yet another one of his own rules. Before, he had been reluctant to kiss Kyoko before he knew she loved him; now he seems willing to use physical intimacy as a way to win her love. Needless to say, it does not work: it's both too clumsy and too late, and moreover, Kyoko stops it gently but firmly, among other things, by reminding Mitaka of who he really is--and by expressing once again her trust in him.
The important point is that none of this is really characteristic of the Mitaka we have come to know for the past five years: rather, this is a man betraying his own ideals and going against his own best nature, driven by desperation. One can still see the flashes of goodness of the best Mitaka in the middle of all this: the way he lets Kyoko go once she makes it clear that that's what she wants, the guilt he feels over his insincerity to Asuna. But the pressure continues to mount, and on a particularly bad day when Godai shows at his door he decides to vent out his anger on him by beating him up.
Which again he doesn't do: circumstances intervene, Mitaka cools off somewhat, and during an uneasy truce he finds out that Godai has a crucial exam the next day. So naturally, he immediately lets him go, because he does not want to have his failure on his conscience. Score another point for his innate decency, but now he's morally and mentally exhausted, and all he can think of doing is to get drunk--another moral collapse. And then he runs into Asuna and under the influence of the alcohol he speaks to her more freely and more harshly than he has ever before.
At this point, Mitaka's fall is complete; the next morning, sobered up and under a terrible shock, he starts picking up the pieces and trying to find his way, slowly letting his best self reassert itself: first the outer layer, the sense of honor and duty, the learned stuff; then, eventually, in the last few pages of his last appearance, also his inner self, the warm, kind, loving human being that we hadn't seen for a long while, temporarily buried under the driving power of desire and of the fear of losing that which he wanted most in the world.
Mitaka is actually punished rather severely for his misdeeds. It's not just losing Kyoko, which he would have anyway; it's not marrying Asuna either, which could hardly be called a punishment: Mitaka could very well like Asuna if only he could let go of Kyoko. They are both very much alike, in the way they personify traditional Japanese upper-class values; and if his initial appraisal of Asuna is that she is a little too shy for him, it should be clear by now that she's willing to meet him halfway. And there is a wonderful scene, early on in their relationship, when Mitaka is still determined not to marry her, but shortly after he has overcome his fear of dogs: he is shown playing happily with the dogs in the yard, in the warm afternoon sunlight, and there is a special glow to the scene, as of a moment frozen in time. This is, I believe, a glimpse of what his life with Asuna could, and will most probably, be.
No, Mitaka's real punishment is mental agony and public humiliation, and it is fitting that it should be his pride that gets so thoroughly squashed, because this, pride, is really Mitaka's main character flaw, even from a long way back. Normally he carries it well, but it shows its nasty face in a couple of his most intemperate speeches to Godai and it is definitely not a pretty sight.
So it is that Mitaka has to swallow his pride and seek out Godai, and admit to him that he's not the man Kyoko wants--as if there was any doubt, but how it must have hurt to finally say those words to your hated rival. And moreover, he has to--he feels he has to, he feels duty bound to--encourage Godai to strive to become a good man for Kyoko. Not an easy thing to say, and Mitaka is far from graceful at it. At this point--the beginning of the last episode in which he appears--he's still too hurt, too wrapped up in his loss.
Because, at this point, Mitaka has been running for a while strictly on his sense of duty--specifically, his duty to Asuna--and this is clearly not enough to go on forever. His heart is still not in it; he resents his fate, and actually has begun to lapse into self-pity. This does not bode well.
And then we see a picture of him as a child, and Asuna notices something. And, when they are both alone in Mitaka's childhood room (a symbol of going back to the true core, to the deepest heart of Mitaka's self?) she tells Mitaka what she has noticed.
And then... then there is a wonderful panel, a moment in which Mitaka is suddenly cut to the quick: through the layers of wounded pride and self-pity and sense of honor and obligation, to his actual heart, his good heart, comes the realization of what he has done, what he was allowing himself to do, and how this festering resentment would ultimately hurt Asuna. And suddenly he's the basically good Mitaka again, and he's not thinking about himself anymore: he's thinking about Asuna's feelings, how he must have hurt them, how he could make her happy again.
It's a turning point, but lest this basic, primitive feeling of concern end up dissolving again into a stiff sense of duty, Takahashi throws in a joke, to give Mitaka what he really needs, to lighten him up a bit. And Mitaka, to his credit, gets it. And he laughs--a little hysterically perhaps, but it is a real catharsis, it's many years of repressed desires and frustrations that need to escape his soul in that moment of laughing. Laughing at himself, perhaps--something he may have never done before--, at the little or big absurdities of life, mostly just laughing to let go.
And he does let go.
And the face he turns to Asuna is again the good Mitaka, the kind, loving person he was meant to be. And he says a few words about their future together, and we know that if he has learned his lesson--the lesson of letting go--it will be a happy future. It was the last piece missing in the training of this very intense young man. It is a wonderful episode: one of Takahashi's masterpieces, and a worthy sendoff to an extremely well-rounded character.