I think what you were going for here was "expletive". "Epithet usually means something else. (There is a rarely used, colloquial meaning to the word, which I found while looking it up, but it doesn't seem to fit in that place either.)"I can tell that each harsh, quaking hand gesture is most likely an epithet."
...and a bit above that:
I might have misunderstood that line, but shouldn't it say either "Do you have what it takes to follow through on that, Hicchan?" or "Do you have what it takes to make good on that, Hicchan?". As it is it looks like a copy-paste error to me.mi "Do you have to follow through to make good on that, Hicchan?"
Also (and this is just a nitpick) in scene 37 (Quiet):
He took that book from a library shelf about a dozen lines earlier - no time to stuff it in his bag."I settle into my beanbag and set about reading my own book that had been buried in my bag."