[Well. He reacts NOW... Mostly by looking startled that Kazuya even caught on that he was even feeling bad in the first place, and then looking rather embarrassed for his behavior. He slumps his shoulders.]

Urgh... It's that obvious, huh...? [He grimaces apologetically.] Sorry, Kazuya-san. It's not anything important, this festival just...

[He hesitates again, not sure how much he should really share. How much is TOO MUCH information?]

...The last time I was at this festival, several friends of mine were here who... Aren't, anymore. That's all, really.