Land of Wind, an auxiliary base on Sunagakure's outskirts, inside the Sandcastle, dedicated training zone.
Unlike the cold, precise, futuristic feel of the base's other sections, this place seemed particularly "rugged" and "primitive."
High-strength energy barriers divided the vast space into several independent areas. The walls and floors were made of specially treated dark gray alloy and synthetic stone capable of resisting powerful impacts and energy corrosion. The air carried faint traces of residual chakra of various natures, along with the slightly pungent mixture of heated metal, evaporating acid, and burning paper.
Inside one training area marked "C-7," a sparring session had just ended.
"Corrosion Release: Concentrated Acid Bullet!"
Yahiko gave a low shout, his hands swiftly completing the final seal.
Before his palms, a fist-sized sphere of viscous liquid instantly formed, its eerie dark green surface constantly bubbling. Then it shot forward like a cannonball, aimed straight at a half-meter-thick alloy practice wall at the other end of the training area, temporarily reinforced with Earth Release!
Hiss-!!!
The Concentrated Acid Bullet struck the center of the wall precisely. There was no violent explosion, only an intense, teeth-grating hiss of corrosion, like cold water dripping into hot oil! The instant the dark green liquid touched the composite wall, which could withstand ordinary B-rank ninjutsu bombardments, pungent white smoke rose from its surface. The solid alloy and stone dissolved, softened, and collapsed at a visible speed! In just two or three seconds, a corrosion hole over half a meter in diameter appeared, its edges irregular and its depth reaching halfway through the wall! The hole's inner walls were smooth, and the remaining acid continued to sizzle, eating away at them.
"Power meets the target. Corrosion speed has increased by 15% over the last attempt, and chakra consumption has decreased by 8%."