ren was excited to test his bad ass powers immediately but he was more worried about his students.
sometimes ignorance is bliss. they have seen his eternal mangekyo so it's better to erase their memories concerning it for good because this information is a sensitive issue. ren will be alright even if bastards like orochimaru or danzo came after him but he doesn't want any harm for his students. besides inoichi's cut wounds have already started closing after ren applied some medicine but his chakra depletion was severe. ren after thinking about inoichi's kind personality , he must have overused his clan's mind posession jutsu during the battle .. sigh. these small children already have to suffer so much and witness the cruelty of war .
ren produced some chakra strings and attached them directly into tenketsu of inoichi which was too easy for him after evolving his sharingan and sensory stuff . this way ren could send his own chakra to replenish his student's chakra easily . this method was risky as body will reject foreign chakra but this was not a problem for ren as with his high chakra control , he can slightly change the properties or disguise his own chakra to become similar to that of inoichi . ren was glad that he had read some books about medical NINJUTSU in the genin and chunin section before ..
komatsukami is really a powerful jutsu but the toll its takes on the eye is too much . ren had straight awakened eternal mangekyo instead of simple mangekyo thus he has no risk of blindness by using his powers . but still ren could use komatsukami only twice a day limit because any more than that will damage his optic nerves . dojustu rely on eyes which rely on optic nerves so ren has no choice but to control his usage . still this drawback can be easily resolved by learning advance medical NINJUTSU as one can easily heal optic nerves in seconds after each use . in time they will become tougher naturally then the limit will increase too automatically. ren planned to absorb uzumaki , namikaze and senju bloodlines after this war ends so his natural healing powers will skyrocket anyway . the first hokage could heal any injury during battle by just using his chakra. but the injuries if too serious then require too much chakra which he had to substitute with vitality ( life force ) thus reducing his own life . on the other hand ren can heal as much as he wants with his infinite chakra and didnt need to worry about expending vitality at all .
after healing inoichi and erasing their memories about his sharingan, ren used simple genjutsu to let the enemy ninja experience some really insane mind torture . in the end they easily got the information out of him while ren ended his life with a single stab in neck . now ren's mindset was toughened as he had made his principle to never show any mercy to scum and one he deems enemy .
the 15 were some genin and chunin from stone village who had mistaken ren's students for patrol genin . their purpose was to get the information scroll from a spy ASAP so they had no hesitating in attacking 4 children to kill them swiftly. well in the end they were unexpectedly stalled successfully till ren killed all of them . ren wasn't interested in that spy because with his sensory ability ren had checked the area of 7 kilometers around him constantly after he killed the enemies . he didnt find a soul except them much less a spy so this simply means either the spy was late or just got captured or killed by leaf . the rules of shinobi were too strict so no spy would dare to change the route on his own decision during mission except gaining permission from village . so either the spy changed direction or got killed and ren was fine with both outcomes .
the journey till leaf camp took 8 more days because ren had decided to teach these brats basic skills so that they can protect themselves during the chaos of war . in the end all 4 of them mastered rasengan which shikaku was second fastest in 5 days despite being the laziest brat . talent is really everything in this world . choza and inoichi had some troubles but ren had assigned one shadow clone to each of his cute students for immediate advice and training therefore combined with their good talent, they also learnt the blue badass orb quickly .
not only rasengan, ren also taught them taijutsu , shirukenjutsu , kenjutsu , ninjutsu and genjutsu all the basic stuff though as time was really short . minato proved his genius and had reached the prowess of an average chunin while other 3 were more powerful than him with their teamwork . of course ren sparred with them 5 times a day and the children cutely pouted because they could not even touch his clothes despite trying different approach everytime. these children dont know the hard trading ren had gone through together with taijutsu beast dai so they didnt have any hope in first place . still the purpose was served as their battle awareness improved with now excellent grasp on each others abilities thus teamwork.
" sensei , what task were you assigned to ? I think you can tell us now that we have arrived at the main base camp!! "( shikaku )
" hmm.. to be honest old man hokage dudnt specify anything . he just assigned me to the frontlines here and told me to babysit you guys while training you so that you can survive this war . hehe.. I can do anything I want anyway because strenght is everything and I can always teach a lesson to some arrogant shits who like to boss people around. anyway , now your sensei has to report the main commander so you guys also report to the genin corps . but dont forget to show the letter of hokage to them while mentioning my name too . they will assign you in somewhat safer battle zone then . but remember my teachings that nowhere is safe in warzone so always take advantage of your surroundings to ensure your survival .. bye for now cute students haha.."