Though Kakuzu is prone to hide his sentiments behind a mask of apathy, he is also one to let them completely control his actions, particularly his anger. For example, we'll be on one of his Jashin-damned get-rich-quick trips, and he'll display absolutely no emotion until I ask something trivial—like where we're going or if we'll be staying overnight at an inn. Before I realize what I've done, my head has rolled meters from my neck. What the fuck. Way to ruin my day, jackass.
But, what absolutely infuriates me more than the random bouts of violence is the fact that I never know what he's thinking or feeling because of his, er, situation. The stitches across his mouth, much like the ones that cover the rest of his body, severed the muscles that allow certain lip movements—smiling, frowning, etc.—and thus add to his mysteriousness by robbing him of the most basic of expressions. (Although, I bet that even if he had the capability to grin, he wouldn't. He's just too used to being a stone-cold shinobi.)
Even still, I wish I could see him smile; not for sentimental reasons, but to prove to myself that he isn't incapable of anything that doesn't happen to be rage, loathe, or indifference. To prove that he's still human after immeasurable years of bounty hunting and organ stealing, I guess, though it completely escapes me as to how someone could keep their humanity intact for that long.
Regardless of my misguided curiosity, it's none of my business. Why should I care if he's still "human" when I barely fit the same description?
This probably seems hypocritical, but I want him to be human, to show myself that even someone as seemingly detached as Kakuzu has the ability to care about something that could consciously care back.
Fuck, now I'm just being stupid. As if that would ever happen.