Rei and Konan were shown their apartment. It was quite big with two bedrooms, a kitchen, a living room, and a toilet. It was obvious that the Mizukage really saw potential in them otherwise they would never get such good accommodation for free. They even received a deed to the flat!

Alas, the most important thing for Rei was not the flat but the slip that would allow him into the library. He could access academy, genin, AND chunin rank material. Yet another show of trust. He was glad about that. This would push them forward quite a lot. ​​

...

The first month in Kiri...

Konan and Rei spent the time looking over Kawarimi and Henge and tweaking it.

The Kawarimi was nice. Just reach with your chakra and swap. Alas, the mass had to be somewhat similar to yours for it to work. That's why logs. God, the shinobi were dunces.

Rei opted to learn Mizu Bunshin and use them for swapping. Especially one with at least five exploding tags on them that would go off during swap. Why destroy nature by chopping logs when you can just gather water into a clone!? One of these days, the Lord of Logs would punish the insolent mortals by making them logged instead of the log!

Using the water clone had many advantages. Not only was he basically quickly transporting water towards his enemy. Water that could be used since he was good at Suiton. But really, these clones do not relay memories and are only one-tenth as strong as the original. Making them go all suicidal by bombing the enemy is a completely valid move! The same goes for playing Shukaku only, instead of sand, using water! All it would need was a horde of Mizu Bunshin surrounding the target and dissolving back into a water source for Rei!

As for henge... he really didn't see the use against anything other than civilians. Oh, he knew why it was mandatory Jutsu. It was a go-to tool for infiltration. There was nothing better than that to fool civilians. And to be honest, during missions, fooling civilians is quite a prevalent activity. Henge had various uses. None of them useful in a battle since an attentive enemy and 'puff', ya dead. But when it came to performing missions?

Bandits come. Henge thirty clones... bandits run.

Need to seduce a man? Kunoichi puts a henge of gorgeous courtesan and done.

Need info from a merchant? Henge into his friend and bam, done.

It was one of the most useful things ninja's ever learned but it was utterly useless in battle. Genjutsu could have lasting effects on the affected. These effects could be discovered. It was much better to just use Henge when dealing with civilians.

Konan also learned kawarimi and henge. Especially Kawarimi since she saw the merit of Rei's idea. She saw a cloning technique for the first time when she opened the bunshin scroll. A day after that, she was already able to form paper clones. Oh... Konan also liked having a blast with her clones. Literally at that.

She even made Rei teach her these seals in English! She didn't know any English other than the words and numbers needed to make the storage seals, stasis seals, and exploding tags but for her, it was enough. She definitely made it into a deadly weapon!

Rei could only bitterly smile. He knew making these three kinds of seals was the limit for Konan. Teaching her just that took an incredible amount of time and these were very elementary seals. She just didn't have the mentality for seals. Except exploding tags. That she could do. She was already devising her own exploding tags.

Konan, in her sadistic streak, mixed clones with the storage seals filled to the brim with her futon paper shurikens. Then made a paper clone made purely out of exploding tags and then whatever mix of the two. Not one of her paper clones lacked at least one exploding tag inside.

The best part? Her paper clones could actually draw seals. Rei used this insight and tweaked Water Clone Technique to be able to do the same. Since then two Konans are drawing exploding tags, storage seals, and stasis scrolls out of real Konan's paper supply, and five Reis who were trying to come up with new more advanced seals. The second bedroom of their flat finally saw some use.

...

The second and third months.

Rei also found a lot of fuinjutsu theory in the library. Nothing extraordinary but enough to push his knowledge forward. But he didn't dare to borrow these books and instead studied them in the corner, trying to be unassuming. He didn't want to tick off anyone that he could make seals. It was a slow process as even if the knowledge was the basics of sealing at most... he was able to find some neat Uzumaki scrolls. This signified that Kiri indeed acquired some scrolls form Uzu.

Rei was mostly interested in Uzumaki battle fuinjutsu but he only got an inkling. He would need a pass to jonin library if he wanted more...

Konan... The more paper clones she made, the more her body became familiar with the prospect of pulling paper together to make a body. She... unlocked her 'logia' powers and became a paper human!

Well, in reality, she just learned how to make her body into paper and how to reverse it. But with the chakra control boost she got by connecting with Rei? With focus, she could do something similar like logia users in One Piece. She, however, had to prevent herself from being hit. But changing the middle of her stomach to paper and make it move 'out' of the strike mid-fight? That was a nasty thing. Or changing herself into a flurry of paper and reforming elsewhere? Or making her torso 'disappear' when she was about to be bisected?

Rei was so annoyed he devised a seal that would prevent her to use it by slightly messing up her chakra control! Nope! No one will pull Crocodile on Rei!

...

The last three months.

Konan's body changing technique stopped being overpowered the second Rei learned how to mold Suiton Chakra into Jutsu. Apparently, her paper can soak up water but it can not soak up water made with Suiton Jutsu unless her water chakra is more concentrated in it. Sucks to be her since Rei was the better one at Suiton from the two.

Rei focused on making his own Suiton Jutsu rather than learning the Jutsu in the library. He learned only a few he found really useful. Konan on the other hand tried to make her futon chakra sharper by molding it in a similar way as some Futon Jutsu did.

Both learned consciously molding chakra for the Monkey hand seal, to make Kirigakure no Jutsu sealless as their nature sensing gave them a clear view inside the mist.

They both also managed to mold their chakra in the way of Dog hand seal. As this one was associated with Water and most Suiton Jutsu needed it. It also helped that their Mokuton practice made it incredibly easy to learn it.

As for the Snake hand seal, they already knew it. It was the only molding of chakra they learned without a hand sign in Ame because it was mostly associated with Earth and Wood. They had tons of Wood creation under their belt and molding their chakra in the way this hand sign did was nothing hard for them.

Konan focused on the Bird hand sign next, for better Futon while Rei started with the Tiger hand sign, which went incredibly well as not only Katon, it was also used for Doton. But it would be months until both of them learn how to do these properly.

Alas, they never learned Jutsu for that reason. They refused to learn hand signs. They knew that once they fix it in their brain that they need hand signs and learn to instinctively mold chakra according to them, it would be hard to unlearn it. No matter how big of a crutch they were. Rei could compare them to a wand for wizards in Potterverse. It was easy to learn them and their bodies got quickly used to them. But it was insanely hard to start molding the chakra consciously on your own once you did get used to them.

It was better to choose the harder route...

Their last week was spent reading various regulations to pass the test. When you are in the library full of Jutsu... you have no time to read these... things.