Disclaimer: Obviously I don't own these guys. I want to, but I do not.
Scar
Kakuzu hated that scar. It was a little hypocritical for him to not be able to stand the sight of a scar when he had so many of his own, but he really hated that one particular scar. It was little more than a faint outline now, hidden beneath a slashed forehead protector, but Kakuzu could never forget it was there.
Every time he saw it, he remembered what happened. Hidan had rushed into battle without thinking like an idiot, once again. This time, he got decapitated. How the immortal managed to scream so loudly without access to his lungs was beyond Kakuzu. Eventually he had stuffed a sock in Hidan's mouth so he could work on the stitches in relative peace. Of course, Hidan made him pay for that later, but it had been worth it.
Now, Kakuzu hated that scar. On one hand, it reminded him that his partner really was immortal. You couldn't kill Hidan, not even when you took off his head. Yet, it also showed that the immortal was not invulnerable. Hidan could be defeated, and there were things much worse than death. Every time he went and did something stupid, Kakuzu couldn't help but wonder if this would be the time he really messed up. It wouldn't be, not if Kakuzu could help it, but what if he couldn't?
AN:Found this is my notebook, decided to type it up. May come back and edit it more later, possibly turn it into a longer drabble series. So just let me know what you think.