If Gai knows one thing intimately, it's pain. He knows all the different kinds. The sharp slap of Sensei hitting him upside the head, the sting of being pierced by Genma's senbon, the nauseating throb of being trapped in one of Ebisu's nasty genjutsu, the needle prick of being called loser and moron, the searing, roaring agony of ripping the gates open.
And he knows how to deal with them, how to get through them, how to push them away into the far corner of his mind until they're nothing but a small irritation. Even better, he has learnt how to use them as fuel for the fire of passion that burns inside of him, always.
Anyway, you could say that he, Maito Gai, is an expert when it comes to pain.
So why?
Why can't he give a name to this new thing he sees in Kakashi's single eye as Minato-sensei leads his rival through the village gates, past the gaping guards and civilians?
Minato-sensei's hand is on Kakashi's shoulder, steering him as if he can't be trusted to walk on his own.
Kakashi's right arm is bloody. Old blood that's crusted into a second skin, that might come off in flakes.
Rin-chan isn't with them.
His heart knows things that his head will never understand. It's always been like that for Gai.
It knows that the look in Kakashi's eye is not like scars, not like bruises, not like broken bones. It won't fade and it won't heal. From now on, it will be there.
And he doesn't know what to call the pain he feels when he looks at Kakashi, when he realizes.
He doesn't even know how to describe it.
But this new pain is like a language, and with dread curdling in his stomach he suspects that one day he, too, will be fluent in it.