V.
"Maa, isn't this interesting?" He says innocuously just as Naruto attempts to take Sasuke down from behind - a move, while not particularly innovative, is sometimes effective and probably would have been this time had Kakashi not interrupted. Of course, that's exactly why he had, but that's neither here nor there.
Instead, Naruto fumbles and falls to the ground with a loud "Oomp!", and Sasuke easily sidesteps the boy. Byakuran moves over to help the blonde to his feet, smiling indulgently. "You almost had him, Naruto."
Sasuke scoffs none too politely at this, but before Naruto opens his mouth to start yet another argument between the two, the masked man coughs pointedly.
The trio then turn their attention onto him, and Kakashi makes sure to let a little disappointment trickle into his expression. "Here I am, creating a training regime that will suit each of your respective strengths and weaknesses all the while allowing you three to get used to one another and working as a team through D-Ranks and lax days, and what do I find?" He pauses for dramatic effect, thoroughly enjoying the mixture of guilt and irritation bubbling between the three of them, before continuing petulantly, "You've gone off on your own and begun without me."
"Well, it's not like you ever tell us anything! How were we supposed to know you weren't just goofing off and reading porn?!" Naruto finally blurts out, agitated. It's almost impressive how long he'd been silent, given his usual tendency to talk over everyone. Still an annoying trait, though.
Kakashi schools what's visible of his expression into a stern look that is not entirely fake as he points out, "Sasuke may have his Clan background and Byakuran, what he's learned from studying; but you're all still just children. The exercises you've been doing are simple enough, but without proper guidance, one of you could have gotten seriously hurt. There's a reason genin are assigned a jounin leader; it's so they can learn jutsu without worry of injuries or of learning it incorrectly." Or, that's one of the reasons, anyway.
He goes on, needing to impress the severity of this situation upon them, "I've been observing you for the past week, hoping one or all of you would come to me with questions or to at the very least inform me of the private sessions, but needless to say, none of you did." Naruto winces a bit, and Sasuke's rigid stance betrays his emotions. Byakuran is not regarding them with amusement, for once; he's been grimacing since Kakashi began berating them.
Sighing, the jounin explains, "Teamwork and training are important, true, but you also need to have the motivation to succeed as a shinobi. We, as teachers, are supposed to constantly test your determination, as well as your strength and intelligence. The life of a ninja is nothing but challenges against your worth, your resolve, and your beliefs. Remember that." They each nod dutifully, and he smiles a bit. "I have to admit, none of us thought this through very well. I had decided not to train you seriously until you asked me. But then you go and train by yourselves instead."
He huffs a derisive laugh, divulging, "You guys remind me of myself as kid. Maybe this is what I deserve." His most astute student levels him with a sad look, and the masked man wonders if the boy has come to his own conclusion about Kakashi's past. Nevertheless, his disapproving demeanor dissipates, and he practically chirps, "I guess that means I'll just have to up the difficulty." The boys perk up at this declaration, and he watches with sadistic glee as their expressions morph into ones of terror at his subsequent instructions.
As much as it pains him to even think it, Gai was right when he'd painted teaching the next generation as a golden opportunity. He can't wait until his cute, little students begin begging him for a break. The three of them pale even further at the smirk on his face, and he cheerfully announces that their new training will begin today.