Leaving both Naruto and Sasuke in the lazy and perverted yet capable hands of Kakashi, who still didn't like the idea of teaching kids A-rank ninjutsu on their first real mission, Sukuna took both girls away to train them.
Knowing that Kakashi had nothing to teach the girls, Sukuna had to take matters into his own hands. At least Kakashi knew the Rasengan for Naruto.
"Okay, what are we learning? Tell us already!" Karin pouted, already too excited to contain herself.
For her, spending time with Sukuna was already a treat. Learning a powerful technique from him was just awesome. She couldn't ask for anything more.
Sakura, on the other hand, sighed, feeling like she was being the third wheel.
"It's simple enough. You'll learn how to enhance your strength using chakra infusion. Looks something like this."
He got closer to a tree and threw a punch. His cursed energy acted much like chakra — the entire trunk was blasted cleanly off before the girls' eyes.
Leaving them with an "O" forming in their mouths, their minds quickly recalled all the times Sukuna said he was holding back when fighting them.
"It's called chakra-infused punch. Though all ninjas do this to some extent, taking it to its extreme gives you a ridiculous degree of strength — like this." He pointed at the part of the tree he'd just destroyed with a single punch.
His cursed energy didn't work exactly like chakra, but with well-placed binding vows, he managed to replicate the famous chakra-enhanced strength of both Tsunade and older Sakura.
It was obvious that this technique was best for Sakura, though Karin would also benefit. Karin had the chakra capacity to be a long-range ninjutsu mistress; however, he himself couldn't teach her those techniques.
He had them — courtesy of Danzo — but he couldn't teach them. He fully intended to give them to her later on. Until then, though, she could benefit from the chakra infusion technique.
"How do we do that?" Karin looked at the destruction in front of her with fascination. This technique was much different from the Black Flash technique he'd used earlier.
"Store up an amount of chakra in your fist and release it exactly when you punch. Simple in explanation but much harder to execute. You need a ridiculous amount of chakra control to pull it off.
"It can also drain your chakra fast if your control isn't good enough, reducing both the impact power and your reserves. There's a suitable technique that goes hand-in-hand with this kind of fighting style, which I might teach you both later.
"For now, though, just start punching away." Sukuna showed them the technique once more, then stood back to observe.
Just as he expected, Sakura got used to it almost immediately. Punching away, Sukuna could even feel the chakra fluctuation from her fists. It was barely there, but it was working.
Karin was much worse, though. Her chakra control wasn't like Sakura's.
However, she had more chakra to waste.
"Karin, use shadow clones and practice with them. Only make three clones for now," Sukuna advised, seeing the red-haired girl's frustration at the lack of visible progress after half an hour.
For another few hours, he kept his eyes on them. Karin still wasn't showing much progress; however, her real results would only show once she dispelled her clones and tried again.
Compared to her, Sakura had already started leaving dent marks from her tiny fists on the poor tree trunks.
'I might have to be careful of her punches from now on,' he mused.
...
By the time Sukuna returned with the girls, Kakashi was also back with the boys. Both looked extremely tired, panting, and their clothes looked worse for wear.
Sakura and Karin weren't much better either — their knuckles were reddened, chakra nearly exhausted, and they looked like they could swallow a human whole.
Surprisingly, no one talked after regrouping. In fact, until the food arrived, they all just minded their own business, too tired to even think straight.
Dinner was a chaotic event.
Food was flying off the table by the second. From the boys to the girls, none remembered their table manners, gulping down food like starving bandits.
"You can slow down, you know. The food isn't going anywhere." For the first time, Kakashi looked embarrassed. Being the adult, their behavior reflected poorly on him.
After ten minutes of silent eating, they finally had enough energy to talk.
"What did Sukuna teach you guys? I have to tell you, Kakashi-sensei was so lazy — he gave me a balloon and told me to burst it using only chakra. Hmph, it's so annoying!" Naruto complained, not caring that the man he was complaining about was sitting right there.
"Hm." Sasuke gave a wordless nod, agreeing with Naruto's sentiment but not adding anything extra.
Kakashi felt wronged. It wasn't his fault that the first step of learning an A-rank jutsu — which, by the way, was way beyond their level — required only simple instructions.
"Nothing much. Just punching trees," Sakura replied offhandedly before shoveling more rice into her mouth.
Naruto didn't get it, but he wasn't eager to ask. Clearly, food was more important.
However, while they were eating, Inari — who couldn't hold it in any longer — finally burst out, venting about his inner demons.
His fear of Gato, how his adopted father died — which, of course, led to Naruto shouting at the little kid.
Sukuna just ignored the entire fiasco. It had nothing to do with him.
"Are you feeling better now, Kakashi-sensei?" he asked, noticing the Jonin looking troubled after Naruto stormed out.
"Huh? Yes, I'm much better now. Thanks for asking, Sukuna." Kakashi smiled his iconic single-eye smile.
"Good. Then how about a little sparring match with me tomorrow?" Sukuna grinned.
"What!?"
"Nani!?"
"Really!? You're fighting Kakashi-sensei!?" Sakura, Karin, and even Sasuke were surprised by the sudden challenge.
"Cough, cough… hmm, why do you wish to spar with me, Sukuna?" Kakashi asked, clearly not thrilled by the idea.
"I need to get stronger too, Sensei. But I don't have anyone better to spar with. You're the best option I've got." Sukuna shrugged.
He wasn't wrong — while he'd done bounty work all around, meeting true powerhouses during those hunts was almost non-existent.
To grow, he had to fight stronger opponents. That was the only way forward. Now that Kakashi was here, he wasn't going to waste this chance.
"Ahem, that might not be the right thing to do. We still have to be ready for Zabuza," Kakashi coughed.
"Don't worry. We'll stick to hand-to-hand only — nothing too dangerous. And I can just heal us if anyone gets injured. Don't worry about it." Sukuna wasn't letting him back out.
Kakashi still looked troubled.
"What? Are you still low on chakra or something?" Sukuna asked with a knowing look.
It wasn't that Kakashi was injured or low on chakra — he was just lazy.
"Hm, a little. I might need some time to recover my chakra. I have to be ready for Zabuza, you know."
"Oh, come on, Kakashi-sensei! It'll be fun! I wanna see his ass get kicked for once. Go for it!" Sakura cheered — for the wrong team, if Sukuna had to point out. Whose sister was she, again?
"Come on, Sensei! We wanna see you fight!" Karin added fuel to the fire.
Sasuke didn't say anything, but he looked the most interested. Kakashi fighting meant an opportunity to copy his techniques — and a chance to see how much Sukuna was really holding back during training.
"Come on, or are you afraid you'll lose?" Sukuna grinned, cornering him.
Kakashi sighed. He knew then that there was no getting out of this easily.
"Nah… I'll—"
...
A/N : Ah I could see Kakashi saying the cursed words. Though he's already a 50-50 man so maybe it might work out for him. Who knows.