My favourite character is, without a doubt, Taiki <3<3
Usually I'd be repulsed by such a "cute" character, but I was instead captivated by his amiable, considerate and sincere nature (might I also mention his sensitivity?) instantaneously. And as my fondness/adoration for him grew, I found myself liking him all the more for his cuteness.
Plus I'm sure his radiant smiles could disarm even the surliest of misanthropists, for it certainly had me smiling in return. Since then, he has dominated a significant portion of my mind, an obsession that resulted in more than 10 hours of precious time being frittered away on reading every Taiki-related novel I could find -- even if it meant having to endure hours of mind boggling chinese, and sacrificing exams... And still I can't enough of him. I really hope that Fuyumi-sensei will write a continuation or conclusion to Taiki's story, because
Tasogare no Kishi, Akatsuki no Sora was quite disappointing in that Taiki didn't receive enough of what would be "screentime" in an anime...
I don't like the older Taiki as much as the 10 year old Taiki, though, probably because he reveals so little of himself as an adolescent.
Keiki comes in second for favourite character, but mainly for superficial reasons, I have to admit. Initially I didn't like his character design so much, in comparison to all the other bishies out there... But after accepting that he was most likely going to be the only good-looking guy in the show (though of course the opinion may differ from person to person), I started paying more attention to him.
Gradually, I began to notice a few more things about him. The first was that he isn't a stereotypical alpha male at all -- the kind that so many romances, and especially shoujo animes, seem to sport in abundance. For one thing, it seems highly unlikely for Youko to fall in love with him and vice versa, considering his experience with the previous ruler and their incompatibility, personality-wise (serious x serious just doesn't work out, unfortunately). Two, he doesn't have a tragic background that attributes to his personality: He simply is the way he is. And there were times when his stoic and straightforward disposition actually came across as being awkward. I even cracked a laugh in one of the episodes when a character alluded to it -- The only time I laughed during all those episodes.
His friendship with Taiki is also very endearing, touching a few chords within me during my perusal of the novels. It was the only time that I was induced to tears for this series.
Not to mention his voice -- something I grew to like most about him as the series progressed, probably because he sounds so genuinely masculine. And not in a boyish way, too. Nor does his voice ever come across as being rude, coarse, or overly feminine. I love his voice even more than Taiki's, as silly as it sounds. But considering how blind people can be under the spell of infatuation (and I *am* infatuated with Taiki)... I think that's quite a statement in itself.
The only thing that prevents Keiki from being my favourite character is the one factor that would make him stand out in your average shoujo title -- His personality. It's not that he's totally devoid of a personality, of course, but his reserved mien is such that people may be given the impression that there is no more to his character than his seriousness and reticence.
My third and also favourite female character would be Renrin. Not many reasons for why I like her, other than that she's beautiful, kind, soft spoken, quietly observant and strong willed. And to top that off, she's also very fond of Taiki.