After finding it, he had suggested that Aqua, Saber, and the others practice their magic near the geyser whenever possible.
Doing so would allow them to absorb mana more efficiently and strengthen themselves faster.
Both Aqua and Saber had followed his advice.
Not only that, but they had also allowed the other members of their respective races to use the area as well.
As a result, many of the magical beasts living around the lake had begun training there regularly.
According to Aqua, the effects were obvious.
The younger beasts were growing stronger faster than before.
Even some of the older beasts had started showing signs of improvement.
For magical beasts, any method that increased their chances of evolving was priceless.
That was one of the main reasons Ash had become so respected among them.
At first, they had only tolerated him because he could heal injuries.
Now, however, many of them genuinely trusted him.
After all, the strange human cub had done nothing but help them over the years.
Aqua smiled.
"Several of the younger Koa could already use powerful magic more effectively."
Saber grinned.
"The Kroxy are seeing results too."
He folded his arms proudly.
"A few of the younger ones are getting stronger much faster than before."
Ash wasn't surprised.
The mana geyser was essentially a natural treasure.
Even if the beasts didn't fully understand why it worked, simply training near it would bring benefits.
Raphael had already estimated that the mana concentration there was several times higher than the surrounding forest.
For magical beasts, it was practically the perfect training ground.
"Keep using it," Ash said.
"But don't become dependent on it."
Both Aqua and Saber looked at him.
Ash continued calmly.
"If you only train there, your bodies will get used to high mana density."
"If you ever have to fight somewhere else, it could affect your performance."
Aqua blinked.
Then she nodded thoughtfully.
"That actually makes sense."
Saber scratched his head.
"I didn't think about that."
"That's because you rarely think," Aqua replied immediately.
Saber glared at her.
Aqua smirked.
A familiar argument quickly started between the two beasts.
Ash was smiling when suddenly his knees gave out.
He dropped to the ground and groaned.
"Fuck... not now," he muttered.
Saber and Aqua immediately rushed toward him.
"Kid, what happened?" Saber asked, supporting him from behind.
Aqua knelt beside him, worry clearly visible on her face.
"Are you alright?"
Ash gritted his teeth as pain spread through his body.
"It's okay... this is natural."
He took a deep breath before continuing.
"It's also one of the reasons I wanted you guys to train near the mana geyser."
He looked at them seriously.
"Now back away."
"And no matter how much I scream, don't interfere."
"This is a natural process."
"You could call it evolution."
"ARGHHHH!"
A cry escaped his mouth.
At that moment, his mana core began advancing.
The Bright Green core at the center of his body started transforming into a Deep Cyan core.
Mana surged through his body like a raging flood.
Impurities hidden within his mana veins were forcibly pushed out.
At the same time, every part of his body was being strengthened.
Muscles.
Bones.
Organs.
Cells.
Everything was being broken down and rebuilt into a stronger form.
The process was incredibly painful.
Black sludge began leaking from his pores.
Ash clenched his fists and continued enduring the agony.
Saber and Aqua watched with horrified expressions.
Even though Ash had explained the process before, actually witnessing it was another matter entirely.
The sight looked terrifying.
Yet they remembered his warning and stayed back.
"I don't know..." Saber muttered.
"I trust the kid, but this looks painful as hell."
"Is it really worth it?"
Aqua didn't answer.
Her eyes were fixed on Ash.
Then suddenly—
A pillar of golden light erupted around her, the pillar of light that signifies a magical beast into Emperor beast.
BOOM!
The shockwave pushed Saber several meters backward.
"What the hell?!"
Saber stared in disbelief.
Aqua's body had begun changing.
Her scales started falling away one after another.
Her body grew larger.
The mana around her surged violently.
More importantly, her lower body began transforming.
Her legs merged together, forming a gigantic fish tail.
At the same time, the features of her upper body became noticeably more humanoid.
Her face softened.
Her hands became more human-like.
Her overall appearance began shifting into something between beast and human.
Black impurities poured from her body just like they had from Ash.
Saber stood frozen.
His mouth slowly fell open.
He finally understood.
This really was evolution.
The process Ash had described was real.
The difference was that when humans evolved, the changes were mostly internal.
For magical beasts, however, the transformation was much more obvious.
Aqua's changing appearance made that impossible to ignore.
As Saber watched the two of them undergoing evolution at the same time, a single thought appeared in his mind.
Why am I the only one left out? he thought bitterly.
Soon, the process came to an end.
For Ash, there wasn't much visible difference.
Only his mana core had advanced from Bright Green to Deep Cyan.
His physical appearance remained largely unchanged.
However, Aqua's case was completely different.
Earlier, she had been a light pink humanoid fish-like beast.
Now she looked like a true mermaid.
Her scales shimmered with beautiful shades of pink and blue.
Her skin remained light pink, but her upper body had become almost completely human.
Her features were delicate and refined.
The only obvious signs of her beast heritage were the scales covering parts of her body and her massive fish tail.
Even her chest was naturally protected by overlapping blue-pink scales.
"Argh... that really hurt like hell," Aqua groaned.
She tried to stand up.
Only to immediately flop back down.
She blinked and looked at her lower body.
Instead of legs, there was now a large mermaid tail.
"This..."
She stared at it in confusion.
Before either Aqua or Saber could say anything else, Ash stood up.