He saw the attack coming, the child's fierce little gambit, and he reacted as he'd said he would. The attack was impressive for only a second attempt, and one so young--had Onyx-Three been an adult it might have broken a limb. As it was, the Sentinel jerked the halberd's haft back in an attempt to block the strike with black metal--the pole, and not a blade.

"Good," he breathed, nonetheless, eyes flicking down to where the strike would have landed. "You are quick. This was a good strike. But--watch the rest of its body. Feet: a step, it will show where I will move. Hands--" and he shuffled to show the 'step,' and slid his hands back along the halberd as if about to move it--"to show what it will do. It will help you. A prediction. Again," he suggested.

The Sentinel paused, then, gaze fixing on Onyx-Three. He was realizing that he had not offered praise. It was something he himself had rarely needed, but feedback was important--Vargas had granted that in their training, and he had just overlooked it. But he did not know what to say. He thought, and thought, a silent moment stretching (unless the child broke it--as instructed--with a hit), before at last settling lamely on a parroted promise: "You are doing well."

He did not "give it his all," yet. These first few steps were as teaching another a new dance: gradual, to allow Onyx-Three to settle into this routine. But he did not go too sedate, so as to draw him into a false sense of how this dance would play out. He would not do him that disservice.

So whilst the movement was slowed, it was not slow; it was swift enough to intercept but slow enough that Onyx-Three could track his movements, learn to predict from what he saw. Could, in short, learn from it. The Sentinel sidestepped, brought the halberd up again to block--and then flicked the bottom of the haft outward, toward the child's calf muscle while he was still stepped forward to strike.

Yet, the praise came again; "A good strike. Continue, and learn. -Again."

"It will take time," the Sentinel rasped, doing his best to keep his language as clear as possible. A sidestep from attack, and he gestured an invitation for another strike.

"The Sentinel travelled, when young." He'd begun this tale, but may as well go over it again: both as advice or a recommendation, and a reassurance that learning did not come overnight. "He was young, and did not know how to fight. Others defeated him. He learned that light, flashed into the eyes, will blind in a battle. That even thrown fruit may be a weapon. That magic can cloud the mind, so that you see other things. Things that are not there," he explained.

Feet paced across the floor, providing now a moving target: steady, not too fast, not too slow.

"It will take time," he repeated, in emphasis.

Watching the child holding his rock, the Sentinel had fully expected--for a moment--for it to be thrown. And had Onyx-Three hurled the stone for his abdomen, well, he might have been prepared, but he'd have also been both surprised and pleased at the child's resourcefulness and adaptability.

As it was, the lunge surprised him more. His block was... well, it was a block, but it was not the practiced grace he'd shown thus far. Instead of a smooth sidestep or a sweeping halberd strike, it was an awkward, sudden hop-shuffle back complete with a grunt, the haft of the weapon barely jerking forward to clumsily crack off the stone. "...Good," he said, but that confusion lingered. "You might also throw it. The stone," he clarified. "But... it is already improvement." He gestured for another attempt, already stepping back into motion, though his mind wondered at the stone.

He did not know any fighters who used ranged, physical weaponry like stones--most used either ranged magic, or close-up physical weapons like halberds--but he could see how it might have its uses. A shame a simple thrown rock would be so weak. Perhaps the Blacksmith would know of something better.

The Sentinel tilted his head, watching with a rather 'puzzled dog' sort of expression as his child launched a rock directly into their own knee. Why? he thought, only to realize that it was just inexperience that had caused it.

There was... faint distress, at Onyx-Three's injury. An unfamiliar feeling, a welling of concern that left him unsure. He reached blindly for his magic, though what came was unhelpful--a burst of spores like those he'd accidentally summoned in the past, drifting for Onyx-Three.

Well--as long as the child didn't outright avoid them, at least the Sentinel would be able to track him later, were he to find himself in danger. But for now-? That didn't really help the knee.

He stepped forward, kneeling, setting the halberd against himself and reaching for the wounded leg with caution. "Is it badly wounded?" he rasped, mostly to himself. "If the child cannot stand... we will find one who can mend it." Nobody really came to mind--Zoisite, maybe? Or even Oliver, somewhere distant.