well i have read some comment about character's sexual orientation. I think Asami,Feilong ...

The author actually stated in an interview that Asami is bi. Idk about the rest of them though.

nope I think Asami is 100% Bi cuz, you don't kidnap a man to rape him if you don't have prior experience or attraction to men. Same goes for Feilong as he was able to easily have sex with Akihito, so he is most likely BI too plus once he admitted his feeling for Asami, he can be categorised more to gay.
As for akihito, although he was a straight, he is gradually becoming gay. Although forced before, he was able to have sex sex with Feilong later, and he now carves for Asami. So, I think his body is more used to being held rather than hold.

Perhaps you can call them 'pansexual' in that the gender of the person is irrelevant to the attraction felt between the characters? Especially Asami and Aki. Pansexual also has a less negative connotation (personally I don't think that 'bisexual' is negative but it does have something of a negative 'reputation' in the media)

There's a difference with being attracted to both male and female and being attracted to people regardless of their gender and gender identity. Pansexuality would mean Asami could also be attracted to crossdressers, drag kings, drag queens, bi-gendered people, androgynes, transgenders, transsexuals etc. I don't think he's that gender-blind, and Ayano precised he was bisexual anyway, one does not equal the other.

I personally never heard of someone calling themselves pansexual until like now, or even heard that word, and I have quite a few openly bisexual friends. I don't see why there would be a really negative connotation to it... Not more than homosexuals at the very least, which our media depict in a positive and casual way anyway. Then again we don't really share the same media with the rest of North America that much... So that's kind of puzzling to me if there's any truth to it lol.

I've heard of it, but I too have never actually known anyone to call themselves that. You're right about the difference though. Bisexuality isn't negative, it's just slightly limited when compared to pansexuality, which is perfectly okay if that's what you prefer. (It's the opposite in my experience, I actually heard more negative things about pansexuality BECAUSE people don't think there's a difference, and therefore, don't think it's real).

Actually bisexuals, the vast majority of them, have a preference between both genders. I realised I managed to not specify it for some reason, it's not that they (and straight people for that matter) can't potentially get attracted to transgenders or wathever either, but everything isn't on equal grounds. Pansexuality is that literally everything is the same to you without any discriminality; basically being gender-blind when it comes to sexuality.
Just in case someone got confused on that, I don't want to mislead people on touchy subjects. Would be kind of not cool.

I think that this is kind of what @Hanne meant when he/she used the term pansexual. Asami is attracted more to certain types of personalities as opposed to the actual gender of the person. He likes people who are not with because of status or money or power, but because they are strong individuals who are not afraid to stand up to him. (That is how I read this story, but I am new to the fandom, so I could see this wrong too, but that is how I took the meaning of pansexual - I know that it means they could also be attracted to transgendered and other types, but being gender-blind usually means attracted to the person and not seeing the actual gender of the person as a barrier to a relationship)

Assuming the author's claim about his bisexuality is accurate anyway, he just happens to like both men and women who has the personality he prefers, and indeed means sex isn't a barrier to the relationship. But it doesn't mean he doesn't prefer to some degree, say men bodies over women bodies, or women bodies over men bodies. He loves both sex, not love regardless of it. Here's the slight difference.

I'm saying gender-blind, but I'm not a native English speaker or around any of them, so how people usually use it I can't tell :P

And what personality would that be? I know that this is coming off as judgmental (then again, he is just a fictional character), but he doesn't seem like one who would care too much of personality traits. Especially, the vibe he was giving in the beginning of series when he raped Akhito. I thought that Asami was the type of guy who would be attracted to physical features for the most part, and then consider the personality later.

Well, as others said, he's attracted to people who have guts and spunk. I only meant this lol.
Anyway, I think he needs that trait into someone, as it's actually specified in the character book and the character interview (well, in this one he's asked what is his type in women and he answers that he notices strong ones) when asked for what is his type. Then yeah, I think the physical traits means a lot to him too. I'm not saying he likes every strong person regardless of their physical features lol. Like, they need to be cute-looking, maybe have a round ass...
I think both are required, you see.