@CinnamonRoll
All right, I'll start with @kanemoto_asuga !! Top down on–
(um, brief aside–I don't actually know how Korean names work? As in whether the given name or family name comes first. I'm like 80% sure it's family name first, but if I'm wrong, I'm so sorry!!! And please correct me!)
–Yoojoon!
Nature seems generally smooth, but there are a couple big question marks. First and I would say most importantly, let's address how his motivations gel with his personality. He's motivated by the idea of acceptance in the eyes of those around him, making them happy with his actions or words or whatnot. It doesn't make sense that Yoojoon would allow himself to appear harsh and competitive when he first encounters people, given that he cares so much about their opinions.
Next up is the bipolar disorder. NOTHING wrong with the fact that he has it (or at least tendancies), but I think it needs to be better explained. Given my (VERY limited) research into bipolar disorder, someone afflicted will have two very distinct sides of their personality depending on the episode they're having. When writing a character with bipolar disorder, it's incredibly important to write out both sides of their personality, examining how manic and depressive episodes will galvanize and dampen their core personality, respectively.
Okay, politics!! I get that Yoojoon can't EXPRESS political opinions, but that sure doesn't mean he doesn't have any. In my humble opinion, all characters deserve placement on the political spectrum, because it can be used as a tool to define how open they are to change! I like to rate my characters on a scale of liberal-to-conservative as a baseline, since it works even for characters who aren't at all politically active.
History is generally solid! Any critiques I have here are going to be small notes. One, his sexuality–how did he overcome his parents' views? Ingrained homophobic views can wreak HAVOC on a person, leading them to be uncomfortable with themselves or reluctant to come out to friends. How does Yoojoon deal with his parents' projected opinions? Two, his band group–how did they make friends so quickly? Most of his character page tells me that Yoojoon is standoffish at first, competitive and kind of grating. So how is he able to make fast friends with everyone in his group?
And that's all I can offer you!! I'll admit I don't know too much about the K-Pop scene, but I really hope I did all right anyway!! And of course, I hope that my notes are helpful to you!! :DD