I'm not sure specifically who the authors of 'Eugene Black' stories are. There could be many independent or emerging authors with such works, or it might be a relatively niche or regional set of stories not widely known in the mainstream.
One common theme could be his backstory. Writers might explore his past experiences to give more depth to his character. For example, his upbringing and how it shaped him into who he is.
Well, without more context, it's hard to say exactly. Maybe Jin Choi had a sad story related to his career. Perhaps he was passed over for promotions repeatedly, or faced discrimination at work which led to a series of sad events in his professional life.
Since we don't have much information, 'choi minhwan first story' could cover a wide range of things. Maybe it's about Choi Minhwan's first encounter with a certain person who had a great impact on his life. It could also be related to his first attempt at a hobby or passion that later became an important part of his identity. It really depends on who Choi Minhwan is and what context this 'first story' is being told in.