Almost a month passed since Ren started training in the underground training ground he built and right now a beautiful and lethal scene is taking place.
We can see the figure of Ren and Senbonzakura surrounded by a storm of blades that seem like cherry blossom petals, while both dance around trying to evade the hit and sometimes a stream of petals-like blades from both sides clash against each others,
But the difference between the two fighter is still obvious, Ren body is filled with shallow cuts all around his body, while Senbonzakura is still in perfect condition,
Soon it is time for the final clash, Ren then trust the hilt in a corkscrew motion and the petal-like blades launch themself at the target in the form of a tornado, Senbonzakura does the same motion but different from Ren, her attack take the form of a drill.
As the two attack clash against each other Senbonzakura's one is easily able to disperse Ren's one and soon hit his intended target pushing him into the wall and leaving a long trench of thousand of cuts in the ground.
After the attack dispersed the figure of Ren embedded in the wall can be seen, all his clothes are shredded to piece and there isn't a place in his body that wasn't cut, thankfully Senbonzakura held back and all the injuries are shallow ones and no vital place was hit.
Senbonzakura come close to Ren and with still the same gentle smile said "Ren-dono remember that the blades are not only controlled by the hilt but also by your will and heart, but still in this month you grew a lot after all you are able to force me to use my Shikai form now, but you still have room for growth"
And Ren with a grin said "Yup, and I was finally able to wound you..." at that moment Senbonzakura notice the single small cut on the left side of her cheek and her smile grew even larger "Good Job Ren-dono if you keep this pace maybe next year you will be able to use Bankai, now hurry up and heal yourself" and then she dematerialized herself leaving Ren alone tending his wounds.
'At least this time I have all my limbs, the first week there wasn't a day where she cut off some parts ears, arms, legs, fingers...she was brutal and she did all that while still keeping that smile on her face...thankfully she did not aim at that place or I'll have nightmares about it till the day I die...even if with Kaido I can still put it back together, that Kido seriously is broken, can heal almost anything but cannot fix what isn't there, for example if the cut arm is then destroyed I cannot do anything about that'
Then Ren start fixing the training ground, and after he did that, he went to the artificial lake to refresh himself, and as he dip in the cold water he let out a sigh and said "It's almost time to go back, and I'm still very far from Bankai, but as I'm now I think the only real danger for me is Orochimaru and let's be honest, he is a danger for almost anyone in this world, in fact even if you kill him in the end he come back to life....."
Then Ren has a crazy revelation "For the left ball of Hagoromo, Orochimaru is Voldermort long-lost brother, both are "born" in 1999, both are really hard to kill because the leave a part of their soul somewhere else, both like snakes, both go repeatedly after children, both have a cult of follower, both experimented on their bodies, both are orphans and both want/will kill their teacher, and in the end are defeted by the same child they tormented"
After a while Ren composed himself and finished bathing, eat something and before starting training again he thought 'In these 8 days left on what should I focus...my training with Senbonzakura can continue, my Hoho got much better I can almost stand on air, but on Kido and Hakuda I'm stuck, on Kido side I do not have enough chakra to cast the 80th and up, and Hakuda well I learned all the techniques and now it's is only about improving my body....Wait! I forgot about Shunko (Instant War Cry) the technique invented by Yoruichi and Soi Fon, for what I remember that is a combination of Kido and Hakuda, and in principe it is similar to a chakra mode'
Then Ren tries to remember everything he knows about Shunko 'Shunko is a technique where one drives and control one of the Kido spell into his own body manifesting as an aura that surrounds the user in combat enhancing speed, strength and endurance while also giving the ability to fire said energy at the opponent, and the point of origin is in the back from there the Kido energy expands to the rest of the body'
'Of know user Yoruichi used Kido of lightning type like Hadō #63. Raikōhō (Thunder Roar Sear) and got as result a lighting element Shunko, Soi Fon instead used Hadō #58. Tenran (Vigorous Tempest) as a base resulting in a wind one, and Yushiro, Yoruichi little brother seem was still learning and used a lower fire-based Kido like Hadō #31. Shakkahō (Red Fire Cannon) but the constant between them is that they all used the type of Kido that they are most proficient'
Then Ren tought about what offensive Kido he is most comfortable at using and soon found his answer.
For the next 8 days Ren continued practicing against Senbonzakura getting still trashed as a result but the wounds on his body are getting less while he was still able to damage her from time to time, and in the rest of the time tried recreating the Shunko with mixed result, the first time he tried he blow off his left arm, thankfully the arm was still intact and he was able to heal it from then he went even more carefully, until on the last day of the training period.
From afar we can see the mountain where Ren's secret training ground his located, suddenly we can see the mountain and its surrounding shaking and all bird and animals are fleeting from it, but after a few second everything calmed down.
Meanwhile in the training ground we can see the painting figure of Ren inside a huge crater, he is shirtless as it was blow over by the activation of the Shunko, and still panting he said "Hah....Hah....It's a first success I was able to do it right, but that is some wild ride so hard to control and mantain...Hah....Hah...It's like going from driving a bicycle to driving the SR-71 Blackbird, it's a miracle if you don't crash and burn, right now I can only use it for an instant and then I have to release the energy, but the result it's not bad"
Then Ren composed himself and took his last spare shirt "Now it's time to go back home, and prepare for Voldemaru attack"