Kurama scoffed from his spot on the couch, his tails flicking lazily.
"Don't get too excited, woman. You're not that talented," he said bluntly. "Even if your soul and spiritual strength can handle it, which is the true upper limit for using shadow clones, your body, specifically your brain, still has to absorb all that memory when the clones dispel, that is why the Multiple Shadow Clone Jutsu is dangerous for a reason, because users might be too conceited."
He snorted. "You could probably manage about a hundred clones for combat purposes. Maybe a bit less for research or anything that actually requires fine attention and thought."
Kurama smirked, his voice dripping with dry amusement.
"Of course, unless you somehow strengthen your spirit further... or better yet, empty your mind. If you can walk around like a thoughtless idiot with massive chakra and a strong soul, then congratulations, the technique would be perfect for you."
Tsunade twitched, but she didn't argue, instead narrowing her eyes dangerously at him.
"As for sensing," Kurama continued, stretching his limbs, "I've lived for centuries. My spiritual strength isn't even in the same league as humans. I'm a tailed beast, an existence born from pure chakra, nature itself. With time living for hundreds of years, my senses, abilities, everything only get sharper, as my soul is strong beyond you."
When Kurama finally fell silent, he folded his paws behind his head and thought privately to himself.
"Unless someone is born with an absurdly strong spirit, or inherits chakra like the reincarnations of Asura and Indra... and happens to be an idiot with barely any stray thoughts... no one can truly take full advantage of my chakra's potential."
Unseen by Tsunade, a faint, amused glint flickered in Kurama's eyes.
If Ron were here, and knew Kurama's thoughts, he would've laughed and said something like, "Yeah, Uzumaki Naruto! He'll be the perfect idiot you're looking for. He's simple, reckless, has Asura's chakra, and in the original timeline, would've ended up being your jinchūriki anyway!"
Meanwhile, Tsunade, unaware of Kurama's inner commentary, simply clicked her tongue and said, "You still did not explain Katsuya's case."
Seeing Tsunade's frustrated look, Katsuya, who was quietly perched on the table, spoke up in her soft, clear voice. "Lady Tsunade, although my current form is small, my main body has given me an enormous amount of spiritual strength. It's comparable to the amount you would summon when you call forth a large portion of my body during battle, which can split off heal and allows communication with multiple split off smaller portions from that portion," she explained patiently. "Normally, when you summon a piece of me, it's just like a shadow clone, only carrying a fragment of my chakra and spirit. It exists temporarily and independently. Once the summoning ends, that fragment simply reintegrates into my original body."
Katsuya shifted a little atop the fruit bowl, her antennae like limbs twitching slightly.
"But this time," she continued, "it's different. I portioned off a massive amount of my spiritual strength, and more importantly, I maintained a connection to my main body in the Wet-Bone Forest."
She looked up at Tsunade seriously. "Because of that, this smaller body of mine isn't a simple, temporary existence. I can continue to supply chakra and spiritual power to it from afar. I can remain here, pay attention to what's happening in the Land of Lightning, and stay active without disappearing. And I am even older than Kurama, with my spiritual strength and the Natural abundance chakra compared to before now seen in the land of lightning, it is easy for me to sense what is happening all around for a long time."
Kurama glanced at her with a curious look but said nothing.
Katsuya smiled slightly. "In a way, Lady Tsunade, you could think of me now as... a living extension of my true self, rather than a short-lived clone which you usually summon. Thanks to this, I can help you more reliably, and also gather information and play around as I want without needing to constantly resummon."
Tsunade blinked at her, a little stunned at the explanation. It was easy to forget sometimes that her longtime partner was far more profound than her small size suggested.
Kurama, with a lazy grin, commented from the side,
"Well, well. Looks like she finally understood, Katsuya sage. Good thing someone around here can multitask without frying their own brain."
Katsuya simply tilted her head in a serene, nonchalant way, letting Kurama's teasing slide past her like water off a rock. While Tsunade also thought about whether she should re-address Katsuya's clone more respectfully, and stop her from calling her Lady Tsunade. To begin with, the real body of Ktsuya sage was never summoned in battle, as she did not pay attention to the world, or was actually summoned, it was more of a small body part with her abilities, not her real self.
Of course, Tsunade was worrying too much, Katsuya Sage, was the only one who actually acted like a sage out of the 3, disinterest from the world, due to her almost infinite life, her main body just sleeps and constantly absorbs and releases natural energy in her sleeping process, to her the concept of age did not exist, Tsunade was interesting, so was her previous summoners, calling them respectfully or even the nonchalant addressing between the summoner and summoned clone was not a problem for her, unlike the stuck up and calculating toad and snake sage, who had thousands of descendent honoring them like some leader, and master.