Responses
I do think zhang zhen xi (brown hair) has a personality, maybe it hasn't been as clear because the chapters are focusing on He's family business and tian/mo relationship. besides being jian yi's partner (platonic or not - idk how the author will proceed), zhen xi has demonstrated being more on the rational and cool side - contrary to the other 3. he's also very understanding, always trying to deal with jian yi's family stuff as well as their feelings. he's the one who's kinda there for everyone always.
i like how we've lost the plot a long time ago, pivoted to a different set of characters before the first set could finish the story they wanted to tell, they are all 15 and get sexualized by the fanbase (and author) a lot, and how the brown haired boy (forgot his name, the one that's always with the light haired boy and has a little sister who's obsessed with him) has absolutely no personality whatsoever