I didn't necessarily connect the golden cows to the ritual in the prologue, but other folks did, so it was cool to see that paid off with the cows coming apart. Really cool imagery.
I liked that Zhou managed to give the Wubei people a fighting chance, even if it didn't work out. The fact that he was so laughably inept at the beginning is making his progression toward a decent protagonist satisfying. I'm definitely team Zhou now, where I wasn't in the first 10 chapters.
The siege and conquering of Wubei's capital was well done. The way the battle was written was very grim and visceral. Good stuff!
While I liked the magical defenses (the four lines, as Zhou called them) I felt they came out of left field. I would have liked to see those sort of defenses foreshadowed earlier, as I wasn't sure (when they started going off) what was happening - whether they were active magic, called by Wubei magicians, or passive traps. So when they started going off, I wasn't sure what was activating them.
That said, I do like the idea that both sides can plant magical traps around their cities. I also assume the Fang-shi knew those traps were there, and knew the only way to trigger them was to send in soldiers to die. Bascially, taking the Zap Brannigan approach to warfare! That's pretty cold, but it's already pretty clear the Fang-Shi only care about results, so it felt in character for them.
I can definitely see your struggle to keep Huang relatable (BTW ... his name changed to Haung at some point in the later chapters, might want to check for typos?) in the face of the Fang-shi's evil magic and the treacherous ways of the Yaart, but I lost a bit of respect for him in this section ... mainly because of his naivety, which I didn't expect. Based on what I'd seen earlier, this felt out of character.
Did he really think that an army and leaders that would slaughter an entire camp under a flag of true would *not* rape, torture, and murder the people of Wubei's capital with reckless abandon? He seemed genuinely shocked when he found the children hanging from the rafter and the agonized mother, and that seemed odd to me. If he truly didn't know that was coming, he hasn't been paying much attention.

I also wasn't completely sold on him saving Zhou. So far, we've seen Huang as completely loyal to his leaders and the Jiin-Wei, and to not only allow, but aid an enemy officer in escaping, is a blatant act of treason. It seemed strange to me that Huang would flip so completely in such a short time, but maybe we'll see more explanation of this in later chapters. I think more foreshadowing (perhaps seeing him defy orders earlier, rather than obeying?) would have sold this a bit better. I've only seen him loyal up to this point.
Overall, the Yaart are absolutely coming across as a ruthless, evil faction, which, while it certainly gives us someone to root for (Wubei) also makes the story a tiny bit less interesting, at least for me. I wish Yaart had some redeeming features (or if they do, we haven't seen them) other than just being dicks. But maybe we'll get some balance in later chapters. If not, it's not a big deal, just a personal preference.
Really felt for Zhou when he reached his burning home, and I hope his family is still alive. Given they were in the cellar, it's entirely possible. I also want to know what was going on with the world of white lines and the red snakes. Basically, Zhou transformed from mildly competent staff fighter (which we saw in the battle with the bandits) to total dual sword wielding badass, who could take down three trained soldiers without breaking a sweat. This *has* to be magical, and that has me really curious about how you're going to explain it. Was he possessed by some spirit of vengeance? Is there some untapped power inside him we haven't seen yet, that even he's not aware of? Either way, it's cool and I can't wait to see what it is.
Good stuff!