Actually the Japanese term for smile is a bit ambiguous; it could also mean laugh. In this case smile seemed much more likely, but both are probably using the same word.
Anyways, I've been liking the contrast in these last chapters and the tangible struggle between the two paths. I think it's...
Certainly the root cause might be fear and insecurity, but he still acts it out externally as if he is underestimating his opponent, so the physical results are the same. The cause might differ, but it ends similarly.
Anyways, I think Itou shows us what further along the path of 'unrivaled...
It would be very strange for someone to have done that themselves. I would wager the author just decided on a whim to put it in English. It's not unprecedented; chapter 268, "On the Edge of the Sword", was also in English. What's interesting is for 268 they had the furigana giving the phonetic...