[It's not really a mask. If anything, he's just too tired to be upset anymore. But after Nephry stayed here by his side this whole time, how could he not be smiling at least a little bit?]

I'm sure anything I could take for my knees would help with the rest. But I think they might be the worst of it. [He absentmindedly reaches down to pat Colonel on the head.] Mostly I'm just... tired.