Kakashi frowned "In that case shouldn't any genjutsu user of decent skill be able to perceive natural energy?" he asked confused.
I scoffed at the question "Who says they don't? I told you it's like seeing color for the first time so while they may be able to "see" the energy they ignore it most of the time because it's not chakra and thus not worth their time in their minds. You'd be amazed at the things people will ignore due to misinformation." I say honestly.
He sighs after thinking about it for a moment and realizing I was probably right and that ignorance was a good reason sage mode wasn't more common.
"Of course being able to sense natural energy is only the first step to sage hood, much like with chakra being able to sense that you have it doesn't mean you can use jutsu. All it means is that you fulfilled the prerequisite condition to qualify to take the next step. Best way I can describe the path to sage hood for most shinobi is learning how to be a shinobi from scratch with a whole new energy and much more risks." I explained seriously.
"How will I know what is or isn't natural energy though if you can't describe it?" he asked understanding me point and wanting to move on.
"That my friend is where you are in luck. See natural energy is currently the densest type of energy in this chamber and using my control I can make it take shapes to ease your sensing of it." I say with a grin.
He easily understood what I meant and chuckled. "You really like making people look bad don't you?" he joked and I merely shrugged.
He was referring to the absolutely unfair advantages I naturally had over everyone else. I was more or less showing off my awesomeness and he knew it. After this he closed his eyes and attempted to sense natural energy but his attempts were painfully amateur in my vision. Thanks to me being able to literally see all forms of energy in the air I could see his spiritual energy in use and it was frankly pathetic. He clearly wasn't familiar with utilizing the stuff as it was uneven and barely able to extend outside his body. I sighed but moved the natural energy past and through his spiritual energy in small shapes to try and catch his attention.-
There were twitches that showed he felt these movements at least a little but it became clear after a few moments that we needed a new approach. I slammed my hand into his chest again to expel the gathered natural energy out of his back and his focus vanished as he coughed a bunch.
"You rely on that eye of yours to cast genjutsu." I stated rather than asked.
"I do, why does it matter?" Kakashi asked confused.
"It matters because it's crippled your spiritual energy. You are so used to using that eye as a crutch for your spiritual energy that you are frankly terrible at utilizing it without your eye. You can barely project your spiritual energy outside your body much less use it effectively to sense natural energy." I said harshly.
"That bad huh?" he asked with a wince at my tone.
"Yes it's that bad. We can't proceed like this or it would be a waste of both our times. One week, for the next week I want you to practice genjutsu without that eye until you run out of chakra. Hell if you can get Kurenai to help you even better." I said firmly.
"And here I thought I never had to do homework again after I graduated." Kakashi complained but I just stared him down.
He left after that and I sighed before writing up a report on the matter and having my cat deliver it to my sensei. I was still confident in getting Kakashi to sage mode in a relatively short period of time but it was definitely going to take longer than I had initially hoped. Without him being able to perceive natural energy clearly we couldn't move on to learning to control it or at least draw it in in a controlled manner.-
With this stumbling block in place I had no choice but to have Kakashi train his spiritual energy properly instead of using that eye for it all the time. Thankfully the man was actually very talented and once he got used to using it without his eye his proficiency with it should rapidly catch up to what it was with it. I assumed a week would be ample time for that especially if he enlisted Kurenai's help with his training.-
The woman was literally called the mistress of genjutsu. For a good reason too as without any form of dojutsu she was easily the most skilled user of genjutsu in the entire village. To the point of even being able to somewhat imitate the mindreading technique of the Yamanaka clan through pure yin or spiritual energy usage. My only concern was that Kakashi might accidentally let it slip about why he needs to train his spiritual energy usage like this if he gets her help. While I am certain Kurenai has a huge advantage in sensing natural energy even without realizing it I very much doubted she had a talent for the stuff.-
So if she notices Kakashi messing with the stuff and decides to mess with it herself it could lead to death for her very easily. She wasn't stupid so if the man "suddenly" achieves sage mode after getting her help she'll likely figure it out quickly. I wasn't trying to keep sage mode to myself or anything but there was a reason I chose Kakashi out of everyone. He was already infinitely close to S rank and so sage mode was honestly just the cherry on top, the final touch.-
For any of the other jonin of the village however it could prove more detrimental than helpful for them to be taught it even if it elevated their power. Sudden spikes of power were all well and good but sage mode wasn't supposed to be a shortcut to power but more a refinement of it than anything. I more than anyone understood this since I was born in sage mode and hadn't left it since. I would have needed to be a fool to ignore the differences between me and the regular people of this world that had been caused by my state of being.