Pronouns: he/him (transmasc)
Xerxes was raised by the streets of Night City after his mother died giving birth to him in her motel room. She was a cyberpsycho and a joytoy (sex worker), someone the government was quick to throw away, so her son didn't end up in the best care facility. He spent more time out of it than in it, often running away to have "urban adventures" with the other kids and getting up to stupid shit with them. Often, he wondered at why the medical responders didn't simply break his neck when they found him screaming and writhing on the motel floor if they were just going to throw him away, anyway.
But despite having those morbid thoughts, he didn't give up. As soon as he was able to work, he would take any odd job he could get, trying to make enough money to get out of the "care home" he was in. He cleaned, he cooked, he learned about computers and how to work them and how to force them to stop working. He figured out you could make some good money if you learned how to take a camera offline for a few minutes, long enough for people to get in and do the ugly work.
As his body developed, he figured out that could be another avenue of money and tried to get into sex work, entirely oblivious to the fact that that was what his mother used to do. He went to the Moxes, a gang that had many joytoys in their employ and made it a point to look out for all of them fiercely. But because he was a minor at the time, they would not let him get involved in that business - for his safety and theirs. They refused to deal in that kind of shit, they told him, consenting adults only.
They brought him on, anyway, though, figuring if they turned him away, he would get involved with someone worse. They had him do tech support or makeup for some of their girls or bussing tables at their bar, and through them, he earned steady enough wages to get his own place - illegally, under a fake identity that claimed he was older than he was, but all the same.
Once he became a legal adult, and he still expressed interest in being a joytoy, they agreed to let him try it, figuring he had seen enough of the ins and outs of the business up close and personal to make an informed decision for himself. He could always back out later and do something else for them if he didn't like it.
But he did like it, getting to meet all kinds of interesting and lonely people, hear their stories, making them leave happier than they were when they met him an hour ago. So, he kept doing it.
But as the next couple of years with the Moxes went on, something about the way they ran their operation started to not sit right with him. He had a big, bleeding heart that he had largely tried to ignore but seeing the Moxes turn people away for not being in their "jurisdiction," so to speak, letting people suffer simply because they happened not to live in the right area of the city, made him uncomfortable.
So, he left and decided he would become independent. Could he do as much without a gang than with one? No, but at least he could say that he tried. He could die with a clear conscious, if nothing else.
Now, he works entirely independently, as a joytoy (under the name X-O), as a netrunner (under the name Xinc), as a mercenary (under the name Xerxes), whatever is willing to pay him the most every day. He keeps his schedule packed with shit and has taken on Ayano as a roommate because she needed a place to go, and he needed someone to keep the lights on in his place when he wasn't there, which was... always, ha!
He later becomes involved with the ragtag team that gathers around Retr0grade's Hibiscus clinic, meeting them all through Ayano (except Rainbow, whom he meets coincidentally through his sex work), and while he tries to be such an aloof lone wolf type, he can't help giving himself over to teamwork again.
Xerxes is a pre-transition trans man who has not decided what he wants to do with his tits yet because he has a lot of clients who like his feminine appearance, and he would feel like he would be "betraying" them in some way. This means Xerxes looks like a woman, he sounds like a woman, and because he's so early into his journey, he may accidentally call himself a girl/woman, too. That is to say, neither he or I will be offended if your muse assumes he's a woman. Like, what the fuck else are you supposed to think? Especially when he's walking around full tits out when he's on the prowl for clients. I will not think it's transphobic for your muse to use she/her pronouns with him before they find out his preferred ones.
If it makes you uncomfortable to use she/her pronouns, knowing Xerxes is trans, that's fine. Online profiles are readily accessible in the Cyberpunk world, and because Xerxes has so many irons in the proverbial fire, it makes sense for your muse to want Something from him and to do their research ahead of time. So, I'm similarly fine with them knowing his preferred pronouns off rip.
Xerxes keeps his hair in the colorful space buns hairstyle (green & blue) very typical of women in the Mox gang. Despite being unaffiliated with them now, looking like one keeps people from fucking with him too much. Not every Mox is happy about this. A lot of them aren't, actually. This is to say that it would not be unrealistic for your muse to assume his gang affiliations, based on occupation and hairstyle.
On a similar note, if you write a Mox muse, feel more than free to have them think of Xerxes as a huge piece of shit and come after him accordingly. While not every Mox is going to think he's the devil, leaving any gang you pledged loyalty to years ago is going to create bad blood, and I'm fine with having him deal with whatever the consequences of that will be.
Like Retr0grade, who is default shipped with Ayano but still open for shipping, Xerxes is default shipped with my OC Rainbow but still open for shipping. If we do have a romantic dynamic between Xerxes and your muse, he won't be dating Rainbow (unless... I mean... you'd like to do a poly thing ig), but if we've already established a strictly platonic relationship, this ship may be mentioned in threads and stuff.
I also didn't know where else to put it, but Xerxes does have a biological half-brother, Ophiuchus. Ophiuchus ran way from home before finding out their mom was even pregnant with Xerxes, so they have only very recently reunited, and that's a whole interpersonal drama Thing as well that may also get mentioned in threads. So, yee-the-fuck-haw or whatever.