Maruboshi Kosuke is one of the most badass secondary characters in Kishimoto's Naruto and deserves more attention. Hopefully this will inspire someone.

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A Temporary Sensei

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"…and Uzumaki Naruto. Your Jonin-Sensei will be Hatake Kakashi once he recovers." Iruka said, causing Naruto to pause mid-cheer and Sakura to freeze mid-complaint.

"Once he recovers?" Sakura repeated. "Sensei… what does that mean? Do we have to wait for him to recover before we can take missions and so on?"

"An interim Sensei has been arranged." Iruka reassured the worried Kunoichi. "He'll be here after lunch, as will the others."

"Hey, Sakura, want to come with me to Ichi…" Naruto began, only for a fist to impact on top of his skull.

"Dammit Naruto, no! I! Will! Not! Go! On! A! Date! With! You!"

"Ow." Naruto muttered as he rubbed at his tender head. "What did I do wrong this time?"

Both of them missed the glare that Hinata sent at Sakura.

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"Team ten, with me." The bearded Jonin said from the door and Naruto watched the Ino-Shika-Cho trio make their way out of the room.

"Team eight." The red-eyed Kunoichi called and Naruto grinned at Kiba.

"Good luck with the test."

"I don't need luck, I've got Akamaru here." Kiba boasted as he sauntered past.

"I was speaking to Akamaru."

"Hey!"

Hinata fought down her giggles as she scurried out of the room, then the last man in the doorway looked at them and Naruto took the chance to examine their temporary Sensei who was wearing a giant Wok on his back and had a wooden peg replacing one of his legs.

"Team seven, come with me." The man said before he turned and walked off. Naruto dashed for the door and promptly got jammed in it as Sasuke tried to nip through in front of him.

"Dammit, teme, get out of my way!"

"Shut up, Dobe! I'm the Rookie of the year, I lead!"

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The training ground that their sensei led them to was a clearing with a small waterfall ending in a pool at the bottom of the low cliff. Several fallen logs acted as benches and a stump had been carved into a seat which their Sensei took, motioning for them to sit down.

"So, introductions." He said. "My name is Maruboshi Kosuke and until your Jonin-Sensei Hatake Kakashi finishes recovering from his mission, I will be leading and training you all. I have been trained by the first two Hokages and fought alongside the Third before he was appointed to the office and had the Fourth under my command in the field while he was still a Genin. I understand the true strengtsh of Konoha, its teamwork and it's Will of Fire, and I will do my best to ensure that you understand them as well. Now, girl, introduce the dark-haired one to me."

Sakura jolted. "Erm, he's Uchiha Sasuke and he's the Rookie of the Year! He's the coolest person ever!"

"And what about his skills?" Kosuke prompted. "Likes? Dislikes? Dreams? Strengths and weaknesses? Elemental affinity? Bloodlimits?"

Sakura looked blank. "Erm, he's good at fighting and throwing things? Oh, and he has the Sharingan!"

Sasuke growled and Sakura seemed to shrink slightly. "What?"

"I don't have it yet." Sasuke grumbled.

"It looks like you don't know the teme as well as you thought, Sakura!" Naruto laughed.

"Then you introduce him to me." Kosuke riposted.

"Sure, this is Uchiha Sasuke, the so-called Last Uchiha after his brother went mad and killed the clan, making him an orphan like me. He doesn't like anything, especially girls squealing about him, but he trains a lot. He can do a fireball thing and… he's arrogant. Good at fighting, though, I'll beat him one day!"

"Sasuke, anything you'd like to correct?"

Sasuke glared at the other two. "I like tomatoes. I hate fangirls who are too stupid to try and be strong and instead want me to rescue them. And my dream is to kill my brother before rebuilding my clan… without the help of fangirls!"

Sakura froze, unable to speak as Sasuke glared at her.

"Okay. Sasuke, introduce the girl to me."

"Haruno Sakura. Bookworm, pathetic fangirl. Hopeless and annoying." Sasuke sniffed.

"You take that back!" Naruto half-shouted. "Sure, she can be mean, but when I was young, she shared her lunch with me when I was hungry!"

"I did?" Sakura asked. "I don't remember that."

"You were my first friend." Naruto shrugged. "But I still don't get why you won't go anywhere with me…"

"That's because you keep asking me on dates!"

"Isn't that what friends do?"

"No! Friends hang out together, its boyfriends and girlfriends who go on dates to see if they want to marry each other!"

"Why does no-one tell me things like that!" Naruto flung his hands wide in annoyance. "See? Sakura's brainy, she knows things I don't! You want to know the different types of Kunai or poltocol stuff, you ask her and she knows."

"All this time, you were just trying to be a friend?" Sakura mumbled in confusion as she thought back over the years spent fending off Naruto.

"Sakura!" Kosuke's calling of her name snapped her back to reality. "Introduce the blond boy to me please."

"Oh, right. Um, this is Uzumaki Naruto, he's an orphan. He doesn't like class and often skips, but on the exercise portions, he just keeps going. His throwing skills are… bad and he can't do the Bunshin…"

"Don't need to, I've got something better now." Naruto gloated.

"…but his stamina and determination are amazing, except for the fact he tends to be very annoying… without understanding why he's being annoying."

"Well, if people would explain it to me…" Naruto grumbled just loudly enough to be heard.

"Sasuke?" Kosuke prompted.

"Uzumaki Naruto. Idiot, can't read, can't fight."

"I managed to beat up Mizuki." Naruto protested, then he seemed to shrink into himself. "Um, ignore that. Jiji says it's classified."

"You can't read?" Sakura asked and Naruto shook his head.

"I can read! Well, some of it… a bit? Look, it's hard learning with no-one to teach you…"

Kosuke stroked his chin thoughtfully. "I see. Sakura, would you be willing to spend some of your non-mission time teaching Naruto how to read properly? It would help him become a better shinobi and you could also instruct him in the difference between wanting to be a friend and wanting to be a boyfriend, thus making him less annoying to you."

Sakura nodded. "Yes, Sensei."

"Well then, let's test out your fighting skills, shall we?" Kosuke smiled as he stood up.

"Ooh! Me first!" Naruto cheered, bouncing to his feet.

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"Ow." Naruto grumbled as Sakura used the medical kit Kosuke had handed her to cut away the shredded sleeve in preparation of cleaning and bandaging the scraped arm Naruto had suffered after he had landed badly.

"You are trying to use the Intercepting Fist without the Sharingan but without working on your speed? That is a bad decision, Sasuke."

"He's good, isn't he?" Sakura sked, concentrating on spreading the antiseptic salve over the cuts and gouges in Naruto's forearm.

"Yeah, even when I used my clones, I couldn't land a hit on him." Naruto agreed, then he flinched as Sakura dabbed at one of the deeper cuts. "Ow!"

"Your anger can strengthen you, but you need to learn to control it. If it controls you, it only makes you weaker!"

"You need to learn how to pack your kunai pouch properly so that they don't spill out." Sakura sighed. "They taught that at the Academy… I think you skipped that lesson."

Naruto shrugged as Sakura began winding gauze around his arm. "Yeah, probably. Most of it seemed so boring and sitting still for that long? How does anyone do it?"

"Using a fireball in close-range combat? Easy to interrupt and it leaves you vulnerable. Only do it at a distance or as a surprise attack!"

"You are rather hyperactive." Sakura agreed, cutting the gauze and tucking the loose end in. "There, leave it on for at least a day and try not to get it wet."

Naruto nodded, then grabbed Sakura and dived to one side, ignoring her surprised yelp. As she sat up, preparing to yell at him, she saw Sasuke lying dazed at the bottom of the tree Naruto had been leaning against, a slight dent in the bark showing that had she not been pulled out of the way, Sasuke would have flattened her.

Kosuke limped across and looked at the dazed boy before nodding.

"He'll be alright, he's just dazed. Sakura, time to show me what you can do."

Sakura swallowed nervously as she clambered to her feet.

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"That was sorta fun." Naruto mused as he walked down the street. "I learned loads from him and it was only our first day! And that memory trick with my clones he showed me? Super-useful."

Sakura hmm'd in agreement from Naruto's back as she rested her chin on the top of his head.

"And that was a great idea of yours too, using my clones to switch you out when needed!" Naruto continued. "I knew you were super-bright!"

"Thanks, Naruto." Sakura smiled.

"All those things you explained to me, that I needed to know…" Naruto continued. "Thanks for promising to explain the differences between boys and girls, I had to rely on magazines for what girls look like without clothes."

"Actually, I think I'll have Dad deal with that one." Sakura shuddered at the thought of giving Naruto The Talk. "I'm sure he can explain it without making you too embarrassed to listen to me in the future."

"Why would I be embarrassed?" Naruto asked and Sakura sighed.

"Never mind. Left here."

Naruto made the turning, using the chance to shift Sakura slightly on his back so that she was more secure as she continued talking.

"We'll have to use some of your clones to get you caught up… Sensei told me how to use them while you and Sasuke were sparring. He also gave me a medical scroll to read, said I did a very good job with your arm. By the way, how is it?"

"It isn't aching any more."

"Really?" Sakura mused. "Huh, sounds like you may have some sort of bloodlimit after all… and it would explain your stamina. Fast healing… yeah, that would do it."

"I don't get it." Naruto complained.

Sakura paused as she considered how to explain. "Your healing takes away some of the tiredness?"

"Oh! Now I get it!" Naruto crowed. "You're really smart!"

"Thanks…" Sakura yawned. "Wow, wish I had some of that fast healing… um, right here."

"Okay!"

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"Chakra training." Kosuke declared from where he was standing on the cliff-face at right-angles to the ground. "Get it right and you can get almost anywhere. Now, have you learned the leaf exercise yet?"

"It kept flying away or blowing up." Naruto half-whispered.

"Really? How interesting. Naruto, go over to the stream and wait for me there while I start the other two off." Kosuke said as he stepped back to the ground. Now, you two, lie on the grass with your feet against the cliff face and channel a little bit of chakra through the soles of your feet. Push it into the rock…"

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"Wahoo! This is awesome!" Naruto carolled as he leapt and dropped into random fighting poses on top of the small pond. "I can water-walk!"

"Thet's great, Naruto!" Sakura called as she slowly walked up the cliff. Sasuke didn't reply as he was too busy trying to cushion his fall as he slipped down the cliff again.

"Keep it up for another half-hour, Naruto, then you can start on trying to tree-walk." Kosuke said approvingly. "Sasuke, you need to use a bit more chakra, otherwise you'll keep slipping. Start the exercise again and see mow much chakra it takes to secure your feet so you can't pull them off the cliff… If you need more help, ask Sakura. She looks like she's got it down."

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"Hello!" the silver-haired masked man greeted them jovially. "It's nice to finally meet you all. My name is Hatake Kakashi and I'll be your Jonin-Sensei from this point on... assuming you pass my test."

"Ah, man." Naruto grumbled. "I miss Kosuke-Sensei already.

"Maah, maah, that's not very nice." Kakashi scolded Naruto while pulling a pair of bells out of his pocket while putting an alarm clock down on the stump. "Now, the test is simple. I have two bells here and to pass, you need to get one…"

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"…and I'll be leading you until Kakashi gets out of hospital… again." Kosuke said, a slight smile on his face. "By the way, Sasuke? I got what happened from Kakashi, your plan was excellent."

"Naruto and Sakura contributed…" Sasuke jabbed one toe into the dirt. "They're not that weak… and Naruto's Henge is useful…"

"Kakashi was quite shocked when Naruto spat a fireball at him." Kosuke chuckled. "Now, since we have a few days to work with, what do you wish to learn?"