Information
personality

In the beginning, Yamato fits pretty much the "rebel/ lone wolf" cliché (which is not very surprising due to Digimon being a kid's cartoon and full of clichés everywhere). Nevertheless it is later revealed that he's not really as cold (or "cool") or maybe even arrogant as he appears at first.

What is most outstanding about him at first is that he acts a lot more elaborate than for example Taichi (this also being a reason for him to object constantly). Compared to the others he's definitely more reasonable than them (except for, maybe, Jou). Probably because he's used to following his own path.

That might be due to the fact he had to learn how to stand on hiw own feet very early, when his dad and him left the other part of the family and moved to O-Daiba. I assume that caused him to be such a "loner" - he has adapted to the fact he virtually had to care for himself. I know it's cliché, but as children tend to rely on their mothers more than on their fathers, Yamato presumably didn't have a person he could really communicate his feelings to.

He was also expected to be a "good older brother" to Takeru, plus he had to care for the household at Ishida's. For example he is responsible for preparing the meals (resulting in him being quite a good cook).

Aside from that, he's also rather outspoken. Meaning that if he has doubts about something or considers it stupid/silly/whatever, he'd say it. Plus he's not easily backing down in order to "preserve the peace" or whatever. Not only in Japan that's pretty rare, so it is somehow guaranteed to cause troubles sooner or later.

This kind of honesty gets him a special personality plus from me, for not a lot of people can actually call it their own. Another example which I consider special or noticeable about this is when he has to look after Hikari for Taichi and she asks him something "difficult" (I don't remember exactly what it was, but probably something close to "Will everything turn out okay?") and he just responds that he doesn't want to lie to her for comfort although she's still little and tells her what's up (i.e. that he doesn't know what will happen either).

Nonetheless, he can quite rude/rough at times, especially when it comes to his own feelings. He's not really a person who desires to share them with other, prefering to keep them to himself and himself alone. That makes him seem very cold & distant, although he is not.

Not only does he care a great deal for his little brother and is always concerned about his condition, but it is also revealed that he tries to shelter himself from (negative) emotions out of the fear of appearing weak or being hurt. That being also the reason for his taciturnity (that let's him appear so mysterious & interesting to the fan[girl]s *cough*).

The only persons he's showing a little of his emotions (i.e. letting them "in" - not in the physical way, pververt!) are his brother Takeru, in form of overcaring and (sometimes massive/desperate) paternalism, and his digipartner Gabumon. Although the latter is more of a silent understanding which does not conversation.

As the series proceeds, he also opens up to Taichi a little and even to the other children very few times (as for example to Jou in the episode where his crest starts to glow). However, those remain seldom.

You can also see that he's not really self-confident in some ways, even though he might act that way. For example, when he notices that Takeru grows up and doesn't need his protection anymore, he thinks he is no longer needed.

Something similar happens when it occurs to him that everyone in the group has changed and grown except for him - he thinks he's not "good enough" anymore and thus leaves them, trying to force development into his character (the only thing that comes to his mind though is labelling Taichi as his rival).

In season two, Yamato is very different from his "former self" of the first season. For example, he's not as closed anymore and a lot more open. He does not seem to have problems/demurs expressing his feelings anymore either.

Furthermore the relationship between him and Taichi has changed pretty much, as they're now "best" friends and aware of the fact their frequent disagreements are just usual and no reason to fight (in other words they can deal with it).

The fact he has a girlfriend then is another proof of him becoming generally more "social" (as is the fact that he's in a band and playing shows instead of keeping his music only to himself [and perhaps close friends]).