The morning sun crept over the horizon, painting the forest in pale gold, but Daigo's mind was already far from the peaceful scene. Last night's brutal Gate trial had left him sore in every joint, tendons still aching like frayed ropes.
But soreness was just feedback data. Pain told him where the weakness still hid, where the human limits still clung stubbornly to his bones.
And if there was one thing Daigo hated, it was limits.
The thought had been brewing for weeks: the idea that pure strength and speed meant little without the ability to maintain them under suffocating conditions. A shinobi's worst enemy wasn't always the enemy it could be drowning, smoke inhalation, choking dust in a collapsing battlefield.
So today's training would combine the Gates with environmental deprivation.Not heat. Not weight.But oxygen.
It was a method too dangerous for standard Konoha training protocols, which meant it was perfect for him.
Daigo spent half the morning scavenging from old ANBU supply caches he'd marked during past missions. From one, he took a worn but functional rebreather mask. From another, a collapsible water bladder. A few river stones, some sturdy rope, and a weighted belt completed his setup.
The destination was an isolated lake deep in the forest its surface still and mirror-like, the bottom dropping into darkness. No one patrolled here. No one came fishing. It was the perfect place to disappear for hours without raising suspicion.
He waded into the water slowly, the cold biting at his skin. The rebreather mask was only partially functional; he had deliberately damaged the filter to limit oxygen flow. This was about scarcity, not safety.
At waist depth, he strapped on the weighted belt and let himself sink. The world above faded instantly light fractured into shifting blue, sound reduced to his own slow heartbeat and the faint hiss of bubbles.
He opened the First Gate. The warmth spread quickly, muscles drinking in the oxygen-rich blood. But the supply was limited, and here, underwater, the body's greed for air was a far sharper threat.
For the first minute, he practiced slow, deliberate strikes punches and elbows into the resistance of water. Each motion was magnified in difficulty, every return to guard a battle against drag.
He forced the Second Gate open. The sudden surge in metabolism hit like a hammer, burning oxygen faster. His lungs began to feel the weight of the decision instantly, the urge to surface growing with each passing second.
Daigo ignored it. He moved into underwater footwork drills small shuffles, rapid direction changes, short bursts forward. The stones on his belt kept him rooted, making each lift of the leg a miniature war.
The lake floor was littered with silt, and every step sent small clouds swirling up, further blinding him. It was claustrophobic, a sensory cage.
When the Third Gate opened, pain bloomed instantly in his chest. His muscles screamed for more oxygen than the damaged filter could provide. Vision began to narrow to a tunnel.
He shadowboxed wildly now, blending taijutsu with improvised grappling motions, imagining himself trapped against an enemy in this exact environment. Every second was heavier than the last, each heartbeat a booming drumbeat in his skull.
A sudden misstep sent him tumbling sideways into a jagged rock. Pain tore across his left shoulder, a deep cut instantly stinging in the cold water. Blood curled upward in dark ribbons.
The survival instinct roared in his mind: Surface. Now.
Panic was worse than pain it destroyed technique, stole time, and wasted oxygen. Daigo forced himself to slow, to breathe as evenly as the mask allowed.
He transitioned into holding postures stances that forced maximum muscle engagement testing how long he could remain functional under this starvation. His mind drifted between focus and a creeping darkness pressing in from all sides.
At some point, he realized he had stopped counting the seconds. Time here didn't matter; only willpower did.
The first real wave of blackout hit without warning. His legs went numb for an instant, a hot rush of dizziness flooding his head. He staggered forward in the water, nearly losing his footing completely.
If he fell and couldn't rise, he would sink deeper into the black.
The thought should have scared him. Instead, it sharpened him. This was the real line where technique broke down and raw will decided survival.
Daigo forced himself upright, clenching every muscle, fighting both the environment and the body's desperate cries for air.
When he finally let go of the Gates and ripped the weights free, the ascent was slow, almost dreamlike. His lungs felt like they might tear from the inside, every meter to the surface an eternity.
Breaking through into the sunlight was an explosion sound, light, air all crashing in at once. He tore the mask off and sucked in lungfuls of crisp morning air, coughing hard enough to shake his frame.
For several minutes, he just floated on his back, staring up at the pale sky. His limbs trembled violently, the cut on his shoulder pulsing with pain.
Most shinobi trained for strength, speed, jutsu efficiency. Few truly trained to keep fighting when every breath was war.
That was the gap he wanted to own.
By the time he reached the shore, he had already decided the next evolution: combine this deprivation with movement under real threat. He would need to build underwater obstacles ropes, weighted dummies, spinning targets. And each one would try to slow him down while the clock in his lungs counted down to zero.
But not today. Today, he would recover in silence. No one in Konoha would hear the story of the man who nearly drowned himself on purpose for the sake of training.
That story belonged only to him.