Training in extreme conditions can better stimulate the potential within the body, allowing Goku to more efficiently improve his strength.
An hour of training can be as effective as half a day of normal training.
If he were training by himself, although he would try his best to push his body's potential, he would definitely still hold back.
Just like training with Master Roshi Grandpa, Master Roshi Grandpa would strictly supervise them, and would release dinosaurs and sharks behind them to stimulate their potential.
"Vulnera Sanentur!"
After Goku put down the giant log and sat on the ground exhausted, Dumbledore waved his wand and cast healing magic on Goku.
Under Dumbledore's precise control, this healing magic could help Goku repair muscles torn by exercise.
After casting the healing magic, he took out a bottle of potion and had Goku drink it.
This was a potion made by Madam Pomfrey that could quickly restore the body's condition.
A moment later, Goku stood up, full of vigor.
"Flintstone Arrows!"
The training continued. Dumbledore waved his wand, and dense arrows appeared out of thin air, shooting towards Goku.
Goku, meanwhile, once again lifted the giant log and practiced dodging.
Later, Dumbledore would occasionally create harsh terrains like swamps and mud pits to increase the difficulty of Goku's training and further stimulate his potential.
In his opinion, the Turtle School training method was essentially about pushing the body's potential to its limits, continuously strengthening its power, speed, and endurance.
This was not a difficult training to understand; it was just that few people could persevere.
When he was organizing the ki magic course last night, he had already figured out the key to Turtle School training.
Although he knew the method, it didn't mean he could replace Goku in guiding the young wizards' training.
Because while the training content was not difficult to understand, how to condense ki within the body after physical improvement, and how to use this ki in combat...
Only Goku, a true martial arts master, could teach these techniques and insights to the young wizards.
Including how to use ki and the body to fight—these things he did not understand.
So he mainly played an auxiliary role; the real teaching still depended on Goku.
The same went for Goku's training; he could only provide maximum assistance by leveraging the convenience of magic, based on the underlying logic of Turtle School training.
If Goku's combat style later required magic for coordination, he could offer many suggestions.
"Alright, it's time for us to go back to school for breakfast."
Seeing that it was already eight o'clock, Dumbledore stopped casting spells and prepared to take Goku back to school for a meal.
Just then, Hagrid poked his large head out from the wooden hut:
"Professor, Goku, I made you some rock cakes. They're fresh out of the oven and still warm."
"Great! I'm so hungry!"
Upon hearing this, Goku immediately dashed towards Hagrid; the morning training had left him starving.
Dumbledore's magic and potions could repair his muscle damage and restore some stamina, but they couldn't alleviate his hunger.
"I think you'll regret it."
Dumbledore, who was about to refuse, saw Goku had already rushed into the house, and helplessly touched his slightly loose old teeth before walking over.
"I'm not hungry yet, a piece of fudge will do."
Seeing Hagrid enthusiastically serve the huge, gray, rock-like rock cakes, Dumbledore picked up a piece of fudge from the table and put it in his mouth.
Although fudge could stick to his mouth, it would at least slowly melt.
But he really couldn't bite the rock cakes; they would make his old teeth retire early.
He could use a Deformation Curse to turn the rock cakes into his favorite dessert, but that would hurt Hagrid's feelings too much.
"I'm eating!"
Looking at the fragrant, warm rock cake covered with raisins, Goku immediately grabbed a sliced piece and stuffed it into his mouth.
"Mmm... delicious... delicious..."
The hard rock cake in Goku's mouth was like a slightly crispy biscuit, having no effect at all.
Soon, one piece of rock cake went into his stomach.
"What good teeth!"
Dumbledore, standing nearby, also praised him repeatedly in his heart.
"Here's more."
Seeing this, Hagrid was even happier and offered a second piece of rock cake.
He was very pleased that someone liked his carefully cooked food.
Soon, the entire batch of rock cakes Hagrid had baked had all gone into Goku's stomach.
"Five minutes full!"
Goku rubbed his stomach, jumped off the chair, and bowed to Hagrid with his hands clasped together, saying:
"Thank you for the meal."
"If you ever want to eat again, you can come over anytime."
Hagrid had a very good impression of Goku and patted his shoulder vigorously.
"Hagrid, we'll come back tonight."
Dumbledore summoned his phoenix and directly took Goku by Apparition back to the Headmaster's office.
Then he tapped the table, and a lavish breakfast immediately appeared on it.
"Dumbledore Grandpa, I think Hagrid is very suitable for learning to use ki. If he trains well, he will become a very formidable master."
Goku, embarking on his second round of eating, said his thoughts while having breakfast.
Hagrid was three and a half meters tall and had a very good physique; he thought he was probably not much worse than Uncle Ox-King.
With such physical conditioning, with a little training, he should be able to master the ki within his body and become a powerful martial artist.
"You mean Hagrid..."
Dumbledore was stunned for a moment, then his eyes lit up.
"Yes, why didn't I think of Hagrid!"
Regarding learning the ki magic of Goku's world, he had never considered adult wizards, always focusing on young wizards.
Because adult wizards' bodies were already set, even if they trained hard, it would probably be difficult to surpass the limit and train ki.
Moreover, adult wizards all had their own things to do, unlike young wizards who could spare time for training.
Adult wizards' thinking was also relatively fixed; even if they knew ki magic was powerful, it would be difficult to make them change their minds.
Even he himself was like this.
Snape, Professor McGonagall, and others had never expressed a desire to learn ki magic during meetings.
Making these Professors frog-hop on the ground carrying logs would be worse than death.
However, he had overlooked one person.
That was Hagrid.
Hagrid, with his giant bloodline, even without training, his body had already reached beyond human limits, possessing the basic conditions to condense ki energy.
Crucially, Hagrid was expelled in his third year, and although he knew some magic, he wasn't that serious about it.
Hagrid's true passion was magical creatures, and in terms of magizoology, he was second only to Newt.
Moreover, Hagrid's mind was relatively simple, somewhat like Goku.
So if Hagrid trained with Goku, he might soon become a martial arts master who could use ki.
In this way, perhaps in the future, if Voldemort tried to cause trouble, Hagrid alone could flatten Voldemort into a meat patty.
So, Hagrid was the savior of this world?