I actually read this when it was initially posted, and then never got around to writing out my thoughts. Sorry for the wait.
One quick thought on the first line: assuming the reader may not be familiar with the geography of Araevis (a reasonable assumption), I would likely be a little more specific with 'The city of Zephii' or 'The isle of Zephii' to be clear that Zephii isn't a person. Or, "The city was pleasant" in the first line, and "Zephii embraced" in the second.
First impressions seem to always get distracted by the technical in my case. The story itself, in a broad sense, feels like a first draft or a synopsis. I don't mean that in the sense that it's rough or filled with mistakes, but in the sense that this feels like you're putting the idea out there in the form of a sketch, but it has yet to be shaded or colored.
I'm all for reading more about Boreas, however, and seeing the dynamics between Astrum and Zephii being introduced, the mysteries about the original Zeph being teased at. The strange dynamic between Perfectus and Mulus I don't quite understand, yet -- nothing about their interaction suggested any sexual or romantic tension. That said, I would be quite happy if that was the intended/continued direction if only because I don't want to read a character that is just a bully. If there is this unresolved tension between them, the antagonism serving as a way to push through repressive barriers is a lot more palatable than just being mean because of rivalry.
Certain things I would have liked to see in this chapter: either a start that's starkly in media res, perhaps with Perfectus in the middle of his routine, going into greater detail to describe the stadium, the contenders, and Perfectus himself; or more time building up to the moment, better illustrating how important it is, how much stress is being built up before the sudden shameful mistake. I also think deeper descriptions for Mulus would have been appreciated, more atmosphere for the room they were in. All of this is dressing, to be sure, but dressing creates depth for the story. But, new story, new characters, sometimes it takes a while to get into the groove with them.
It's been a while since this was posted, and knowing you, you may already have four or five chapters written in advance that you just haven't posted yet, but I do want to see where this goes and see how the writing evolves.