Kojiro
Kojiro felt feelings enter his mind he knew were not his. He could feel serenity that had no place in his mind, a technique tainted by it's owner, and he knew whose emotion were so calm. He despised people who would interupt his duels with an assault on the mind. He'd run into several Yamanaka who'd tried.... it hadn't ended well. He thought in response to Zume's unwelcome intrusion.
And here I was assuming you were a wise man, but here you are, looking into what you don't understand.
The incoming shrinking spirals were the least of his worries. They dared pass through mother Earth, when his large rock style dictated it. His hands lazily started making a series of 6 handsigns, then repeated them quickly. His focus wasn't on countering the jutsu, he had it covered.
Earth Release: Moving Earth Core
He had hoped to save that as an ace against his opponent later, but it couldn't be helped. He could feel the circles moving, and if they were fashioned after how he imagined, that would stop them.
The technique however was countered, by Kojiro himself with a second release of it, moving in the opposite direction. The technique generally elevated or lowered the terrain around the user in a square box. Kojiro had used it to elevate the terrain, then pushed down on it with an equal force. That would compress the earth itself, making it much harder to pass through, and more importantly the compression would grab the circles by the sides, not head on.
Kojiro imagined front and end of the cirles were the hard part, probably bladed to pass through without difficulty of the objects they passed, they probably had enough power to cut Monohoshi Zao. But from the sides, they would be vulnerable, and in addition, if they were curved, they would take even more damage from the earth pressing from above and below, unbending it. The sheer movement, should it fail to stop it, would also threatened throw off their little perfect circle, and have them crash into eachother.
Kojiro's focus wasn't on that however. It was staring at Zume, his killing intent took on a new form, a new terrifying form. Mere fear was something that a few men could indeed take straight on, but there was something more from a constant assault on one's psyche from more and more directions.
His killing intent filled every recess of his mind, taking all of his focus to not be overwhelmed by it himself. He projected it straight at Zume through his eyes, whose bright blue sage color had become frieghtening, increasing it and renewing it constantly to redouble it's effect. As long as Zume was saw his eyes, the intent would increase with each renewing, and while doing so relieved Kojiro from the last wave as he made a new one, but the old ones would linger, and continue to build on Zume as long as his attention was on Kojiro. Seeing every detail of Kojiro's eyes would also increase it, as was an increased perspective as he would notice every single detail of it more than most, affecting him more than most. In addition, him reading Kojiro's mind would double whatever hit he was taking from the standard killing intent.
The intent would intensify to a madness, flashing every fear a man could have of the line between life and death. Not only of the initial feeling of simply dying, but the thoughts of those close to them fading, thoughts of life becoming terrifying itself. It would build and build til the many thoughts driven by the intent would drive a man to madness, tearing his psyche to shreds.
In essence, as long as he kept looking, and reading, Zume was putting himself in greater and greater danger from reading what what Kojiro assumed he wouldn't understand. The intent didn't come from chakra, or from mere thoughts, or hormones, or atoms, or things the eyes could see or be helped to see, but a flash of Kojiro's soul at it's most viscious. Even if Zume had the most steeled will on earth, and the effects were paltry, they would only keep building, and all his observations skills would only increase the speed of the threat. To keep looking would not end well.
"I am not a sage of a mere animal, I am the sage of humans, that allows me to feel very deeply the emotions we have. We too belong in nature, at our very core, we are part of it. The very soul is natural. I came here seeking a natural fight, not to be examined."