Hatsuharu, Kyou and Yuki

Backstory

Hatsuharu, Kyou and Yuki are all members of the cursed Sohma family, each possessed with a vengeful spirit from the Zodiac story (ox, cat and rat, respectively). Thus, they all share a bond immediately. The resentment held by such animals, is also present in those possesed by them, as can be seen in these three characters particularily.

Kyou & Yuki

In the Zodiac story, God invites all the animals to a banquet, the rat however lies to the cat and tells him the wrong date, tricking him into missing the banquet. As a result, the cat also loses his place in the Zodiac. As Kyou is possessed by the cat's spirit, he is ridiculed by those in the Sohma family aware of the curse, as being stupid due to the rat's trickery and his exclusion from the Zodiac, leading to his resentment of Yuki.

Yuki & Hatsuharu

Haru has a similar motive for his original hatred of Yuki, being possessed by the Ox of the Zodiac. In the story, when reaching the banquet, the rat who had ridden the ox on the journey, nimbly jumps off and is announced to be the first there, thus the first of the zodiac. As with Kyou, Haru is also ridiculed for the ox being used by the rat. This starts a constantly growing hatred for the boy posessed by the rat, that Haru has barely even seen. This hatred caused Black Haru to appear. His hatred of Yuki continued until he finally spoke with him, and revealed his hatred. Yuki however helped Haru to realise that he was not at fault for the actions of the Ox, helping him face the ridicule. From that moment on, Haru becomes very protective over Yuki, and often visits him when he is imprisoned by Akito.

Hatsuharu & Kyou

Unlike with Yuki, the cat and ox have no previous resentment to taint them, so Kyou and Haru share a much better relationship as children. Well, as good a relationship as these two hot heads can possibly have. As kids they used to train at martial arts together, and do seem to share a good relationship, enough for kiddy Kyou to help Haru find the toilet ^^.

Manga/Anime

By the time of the Manga & Anime, the essential element of Tohru has been added to the mix, meaning a massive change for the characters. Yuki and Kyou still hate each other, and argue daily, but according to Haru, they're getting much better. The three are first reunited in chapter 13 of the manga, and episode 10 of the anime (Make it Clear if it's Black or White). To get their attention, Haru trips Kyou, showing their relationship to be though rather violent, still as playful as ever, later followed by Kyou getting Haru in a headlock. Of course they still fight (or battle), but it's more of a friendly rivalry than out of. Haru's admiration of Yuki is still evident, if not grown, even confessing to Tohru that Yuki was his first love. Throughout the series, the concern that Haru shows Yuki never ends, defending him from the dreaded invading Ayame, his constant observation of Yuki and Kyou's progression. Despite all the dissagreements, and misunderstandings that arise between the three, they always share the curse of the zodiac possession. Also, the scene with the Student Body President is just priceless! Where Haru has to 'proove' his natural hair colour, resulting in the absolute outrage of Kyou and Yuki.

Why?!?

as taken from my application in part
For a start I absolutely adore all three of them on their own, but when all three are together, ahh the chaos! Kyou always seems to be able to bring out 'Black Haru' whereas Yuki always seems to restore him to calm. I can't resist the love/hate relationship between the three, almost every scene is either hillarious and of course touching as they all have to deal with the curse (and their family) together.