A/N: Right. Sorry for the long wait/short chapter combo. BUT HEY IT'S HERE.
After this, it may be best to basically treat this as a mangaverse AU, as it starts pulling away from the official story even more.
"Faster. I said faster, not slower; now make sure to- Ugh. Dodge, not block. Really, what was that?" Kakuzu retracted the tendrils in his arms, leaving his previously crouched stance to stand upright. "Make sure you're not just flailing around, would you?" he asked the young ninja before him.
The boy, no more than thirteen, judging by his appearance, staggered to his feet, flicking spiky, pale blonde hair out of his sea green eyes. He stumbled for a moment, refusing to support himself on the wooden training dummy next to him. He glared at Kakuzu, his mouth twisting into a scowl at the older ninja's exasperated comment.
"I'm not flailing," he snapped. "I just made a bad call. This time I'll-"
"Just a bad call?" the Akatsuki member interrupted him, crossing his arms over his chest. "Do you realize what that 'bad call' would cost you in a real battle, Yuu?"
The boy, Yuu, sniffed derisively, narrowing his eyes at a lesson he had heard before – repeatedly. "Yeah, the mission, the battle, whatever. Now can I just-"
"How about your life?"
The young boy flinched away for a moment, but quickly forced himself to stand tall (tall being a relative term), glaring at his teacher. "It's just training, anyway; why does it matter if-"
"Are you listening to me?" Kakuzu pointed an accusing finger at the spy-in-training, dark brows knitting together. "Training or not, you can't let something like that happen in a real battle. And in order to do that, you need to make no distinction between training and a real battle. Aim to kill, fight as if your life depends on it, and don't make mistakes. Understood?"
"But-"
"Understood?"
Yuu's frown deepened, but he lowered his gaze, directing his glare at the dead leaves at his feet. "Understood. It won't happen again, sir."
"Good." Kakuzu nodded, walking past the boy on his way back to the hideout. He paused as he went by, momentarily resting a hand on Yuu's shoulder. "We're done for today. Get back inside."
Yuu nodded, but didn't move as Kakuzu continued on his way. He instead kept staring at the ground, his brow furrowing slightly. Don't make mistakes.
Abruptly, he spun around, whipping a kunai from the small pack at his waist and hurling it toward a sand-filled dummy. The knife buried itself in the fabric of the dummy's chest, and sand poured out with a satisfying fssssshh, leaving a small pile on the ground. Yuu, his expression unchanging, walked over to the dummy, picked up the weapon from where it had fallen in the pile of sand, and slipped it back into his pack. "Perfect," he whispered. Just as he was expected to be.
Hidan yanked the spike out of his chest, standing up and shooting a glare at the shinobi lying dead on the floor. "That was just sad," he grumbled. "And to think you're supposed to be a jonin. That battle was practically an insult to Jashin-sama."
Of course, the corpse didn't answer. Hidan snorted and turned toward the doorway of the basement, leaving the body for Zetsu to deal with. He started to climb up the stairs, only to nearly crash into Kakuzu.
Kakuzu grimaced slightly under his mask, leaning around Hidan to examine the mess left at the bottom of the stairs. "That's disgusting, Hidan. Can't you do your pathetic rituals somewhere outside?"
"Hey, watch your mouth!" snapped the Jashinist. "Besides, aren't you supposed to be training that creepy brat you call a spy?"
"We finished earlier than expected."
"Yeah, sure. You just happened to finish early. Because you just can't bear to tire out the poor wittle boy, can you." Hidan scowled as Kakuzu pushed past him, no doubt to re-check the security under the base. The place was supposedly an abandoned dojo, not "structurally sound" enough to allow anyone inside. But just a warning wasn't much; the criminals got trouble fairly regularly from everyone from nosy ninja to stupid kids, trying to be "brave".
"So, what's the real reason for this 'abridged' training session, Kakuzu?" The missing-nin didn't answer, and his partner turned back up the stairs with a snort. "Whatever. If nothing else, maybe I'll ask him myself."
Kakuzu didn't even spare a glance at him, continuing down into the basement, carefully stepping around Hidan's newest "sacrifice" along the way. To be honest, the boy was certainly above average, considering his age. But "above average" wasn't good enough in the Akatsuki. If the child wasn't ready to take on the most dangerous opponents in a real battle, he had no place here.
Hidan, of course, didn't understand any of it. He had only come a couple of years ago; as far as he was concerned, Yuu was just the "creepy kid" who they kept around for no apparent reason. He hadn't been there when they had found the boy, about eight years ago now.
Kakuzu was by no means a sentimental or sensitive man. He had murdered countless people, whether for money, to take their hearts, or just out of blind rage, and it was almost unheard of for him to express any regret or guilt over these kills – it was anyone's guess as to whether he even felt any. And Yuu was by no means a lovable child. Maybe it was due to the Akatsuki's influence, or maybe it was just his nature, but the boy had, over time, grown to be stubborn, arrogant, and uncaring. But all the same (or maybe partly because of this similarity), Kakuzu felt that this boy was somehow his responsibility, if only in part. And, at the same, time, he couldn't allow anyone working for the Akatsuki to even be capable of slipping up – especially a spy, hand-raised by the criminals themselves. That would be outright humiliating.
So, through the last eight years, through all the members who came and went, Yuu had never gotten any slack. He was expected to be precise in every strike, unhesitating in each attack, fearless, merciless. He couldn't be allowed to lose.
Kakuzu thought in silence as he examined the traps and diversions, planning the next few training sessions. He seemed to be in charge of Yuu's training significantly more often lately, most likely due to the recent discovery of Yuu's chakra nature, and the subsequent decision to start teaching him how to use it properly. Kakuzu, being the only Akatuki member adept at the use of the same lightning-type chakra which Yuu possessed, therefore ended up working with the boy far more often.
Kakuzu, finished with the security, rose to his feet, about to return to the upper levels of the base. However, he was somewhat delayed when, without warning, something burst out of the ground in front of him, causing him to leap backward, drawing a kunai from his sleeve.
He relaxed, however, when the thing opened, revealing a familiar two-toned face.
"Dammit, Zetsu, watch it," Kakuzu snapped, slipping the weapon back into its hiding place. "You should know perfectly well how dangerous it is to startle me."
Rather than replying to Kakuzu's irritation, Zetsu responded with just three words.
"Sasori is dead."