Akiyama Yukuro (暁山 遊黒).
Akiyama Hiraku (暁山 拓).

• Yukuro is mildly depressed. It doesn't reflect obviously; he's perfectly happy to socialize, go out, do things, make friends, and the like. In fact, he's rather good at making friends. Instead, it manifests itself in Yukuro being reserved about himself; he doesn't talk about his past or his feelings much at all. Because he appears as calm and cheerful, if not very energetic, most people don't think twice about it. Even those that try to ask often get lightly laughed or playfully snarked off, because Yukuro is insecure about himself existing and finds too-personal chats scary.
  
  
• As far as Yukuro knowns, he's an unwanted child. From his perspective, his mother dropped him with his grandmother when he was very young and not only never came back, but the person who was his father never came by either. He feels like he was just discarded, and it fuels that insecurity about himself. He tried to work hard to help his grandmother, and he's very grateful for how much she loves him, but it can't erase all those unpleasant feelings. It's one reason he struggles hard to connect to people deeply, and why he tends towards keeping others slightly at arm's length.
  
  
• Despite this, he can't talk badly about his parents at all. While he will bitterly call himself a "discarded child" if someone digs enough or he's upset, that's the most negative thing he can come out with. For his mother, he remembers her clearly, remembers her reading him stories, bringing him trinkets, showing him pictures, all related to the digs she's come back from. About the ruins, about the culture, about the area, all of the stories and those times are things that he holds dearly and warmly, even if there's a sad tint to all of them. For his father, he has memories of a non-Japanese man with kind eyes and a gentle voice, who often visited him and cooed at him, though not quite as much as his mother. However, as that's all he can remember of his father, he can't defend him like he'll defend his mother. He just makes an uncomfortable sound and then moves on.
  
  
• Though he doesn't know it, Tron is his father, making V, IV, and III his older half-siblings. His mother, Hiraku, became very close with Tron, but wanted to focus on Yukuro before dealing with three other children, even if one of them was an adult. No one else seems to know about this, either, and no one can tell him about his father at all.
  
  
• He uses people's first names pretty exclusively unless they ask otherwise, though he does use proper honorifics.
  
  
• He tends towards being fairly snarky, and sometimes takes on a deadpan tone with it. This isn't an attempt to mock people or anything; rather, it's his attempt to deal with his feelings and situations through humor at times. This unfortunately comes with self-insulting snark a lot.
  
  
• Yukuro is gay, and rather unashamedly so. While he doesn't talk about it with strangers, he's more than happy to make comments on others when with people he can relax around. Two noteable situations are 1) when he told Alit that it was unfair to have him as an enemy, because it was too hard to fight such a pretty man, and 2) when someone made a typical teenage comment about his brothers' appearances, and he said that he felt he couldn't "ethically" comment on that. He also can and will stare or oogle guys he finds attractive -- and unashamedly so.
  
  
• He believes that people always use each other. It's not a good thing or a bad thing inherently, it's just something that happens. Friends use each other for company, after all. What matters is your feelings for the other person, whether you care for them or not; that's what makes it just normal or what makes it cruel.