So my initial online username was Kazami (as in Yuuka Kazami, the Touhou Project character!) for the longest time. That is, until the Discord naming system changed in 2023. And Kazami, being a very common, popular name was obviously taken (shucks!). So I added the Ha- at the start. I'm not really sure where the idea of that came from. I just thought hakazami rang nicely in my ears.
"And what about HKZ?". During this period, I was very much engaged in the Bullet Hell games community, which was composed of many retro, old school shmup players. And a lot of them had 3 letter initial names, mimicking how arcade games back in the day used to limit your name to 3 letters to store your scores. And so, it was easy to get HKZ from hakazami, and that's how I've rolled since then ...