Okay, it's been awhile since I harassed you, so I'll give it another go.
I didn't have any particular beef with the chapter as a whole. Now that the little Jin has grown up a little, things aren't so unbelievable for me, although I still found parts of it boring. This is likely due to its length: after 37 pages (when you properly double-space everything), you really don't accomplish much except for a lot of inner thinking. In a normal-sized novel, this is somewhere between 1/10 and 1/20 of the total length, and all you do is have two fights and some chit-chat. The total in-world time of this chapter is probably under an hour.
However, I think the biggest problem I had with it was the actual fight. You have 5 whole pages of building up to the fight, and it's literally over in 2 paragraphs. 2 measly paragraphs. Perhaps you meant it that way; I don't really know. To me, though, it feels like a letdown. I understand that Teruss is really just this sissy who gets his way because he runs away from anything threatening, but the way you portray him it looks like he doesn't even know how to fight. I'm pretty sure you don't get arms the size of someone's legs from doing nothing. I really feel like, if this is going to be the Fight That Changes Jin's Life, it should last more than 223 words and have a little bit of suspense in it.
Now, I'm going to give you a warning that I haven't read all of the previous chapters yet; I've been busy, and yours is one that I generally have to be in a certain mood to critique. However, given your intro, I'm not really seeing how this explains the reason for you spending so much time on their early lives. There's the fight, where he forges and kills his first person, and then another fight, where he forges again with more knowledge about what he's actually doing, and then manages to get away from the Hesk. You have an instructor (the voice), so nothing in his past really comes into play here, except maybe a little bit of Talven's early lessons. Still, It doesn't seem all the necessary, and it could easily be shown through flashbacks or just inferred in the present. So what exactly is the reason you've spent so much time on their early lives?
The Hesk are nifty enough, I suppose. They're pretty standard lizardmen (regenerative powers, scales, etc.), but I'll wait to see what you do with them before passing judgment. Dunno if I'd call them ninjas though.
Your second fight is better by far. Things actually happen in it, and we learn more about the actual process of forging. It was much easier for me to read for this very reason.
If you were to expand the first fight, to give it some substance, I would recommend breaking this into two chapters. One for the first fight and the aftermath (choosing weapons and whatnot), and another for the second fight. 8k for a chapter is getting a bit lengthy. You could even end the first chapter with a good cliffhanger. A good place to cut it would be when the attendant comes in and says "She's dead." Then I *want* to turn the page to read what's happening. I would also recommend cutting down on the amount of Teruss' life that you dump on us in one place. It's quite telly, and only some of it holds relevance at this time.
Anyway, keep it up (not that I could stop you anyway). You'd just better get that ax sharpened, 'cause you're going to need it eventually.