Is That... the Eternal Treant Sentinel?

"Thalissa, have you ever heard of the Ancient War Mother Tree?" 

The voice of the elf, Amy, trembled as she spoke.

The unicorn, Thalissa, glanced at Amy and replied softly, "Of course I have. The Ancient War Mother Tree is the source of the treant lineage."

"The relationship between the treants and the Ancient War Mother Tree is akin to the one between your natural elves and the Elven Mother Tree."

"Yes!"

Amy sighed deeply, "Until now, I had never seen the Ancient War Mother Tree. Even in the capital of our Elven Kingdom, there is no such tree."

She continued, "I've only heard that there is an Ancient War Mother Tree in the ancestral lands of the elves, one of the oldest guardians there!"

"Amy, what are you trying to say?"

Thalissa followed Amy's gaze.

Moments later, Thalissa gasped, "You can't be suggesting that the towering tree, hundreds of meters high, is the fabled Ancient War Mother Tree?"

"Yes, I believe it is," Amy declared. "Though I have never seen the Ancient War Mother Tree in our ancestral land, I can feel the presence of the treant lineage within this tree."

"What kind of treant can grow to be hundreds of meters tall?"

"Unless it is a Tree God!"

"So, I suspect it must be the legendary Ancient War Mother Tree!"

Thalissa shook her head in disbelief, "This is too incredible! I'd sooner believe that tree has evolved into a Tree God than accept it as the Ancient War Mother Tree!"

Amy countered, "Then how do you explain the ancient treants we just saw? I don't think they were birthed by nature alone."

Thalissa fell silent, understanding Amy's implication. That ancient tree must be the fabled Ancient War Mother Tree, the progenitor of those ancient treants.

"Let's go, into the Golden Oasis!" Amy declared. "Regardless, I must uncover the secrets of this oasis!"

Thalissa hesitated, "But Amy, there are four holy-rank undead dragons there..."

Amy laughed, "My dear Thalissa, since when did you become as timid as a flower sprite?"

"I am not!" Thalissa denied instantly, gritting her teeth as she flew towards the distant Golden Oasis.

"This oasis has grown much larger. It wasn't like this before!"

"Compared to the appearance of the Ancient War Mother Tree, I'm not surprised by the changes in the Golden Oasis. With the tree's help, it could become even grander."

Amy said, "Maybe in a hundred years, this place will rival our Forest of Life!"

Soon, they halted about three hundred meters from the oasis's edge. It wasn't that they didn't want to enter, but they were being watched. 

Beyond the four undead dragons in the sky, the towers and fortresses on the perimeter walls had all locked onto them. Any closer, and they would be attacked.

More crucially...

Behind the walls stood over a hundred golden-armored treants, towering dozens of meters high, glaring at them with hostile intent.

"Amy, these treants seem different," Thalissa whispered.

"You're not mistaken," Amy nodded, her delicate face showing shock. "They are Eternal Treant Sentinels, holding a higher status than ancient treants, akin to how Sun Elves are to our kind."

"Eternal Treant Sentinels?!" Thalissa exclaimed. "There are scarcely any in your elven capital, yet here there are over a hundred?"

"This only strengthens my belief that the ancient tree is indeed the Ancient War Mother Tree," Amy said. "Only it could nurture so many Eternal Treant Sentinels!"

Thalissa took a deep breath. She, too, was now eager to uncover the secrets of this Golden Oasis and the mighty force behind it.

...

"The Eternal Treant Sentinels don't want us to enter the oasis," Thalissa said. Forced entry was not an option; the undead dragons circling above could easily subdue her. Especially the enormous zombie dragon... calling it a Zombie Dragon King wouldn't be an exaggeration. It alone could tear her apart in battle.

In the Sacred Continent, the unicorns were among the most powerful and intelligent species. But against dragons, they were outmatched.

"I'll try talking to them," Amy said. "I'll get us an invitation."

She flew towards the Eternal Treant Sentinels by the wall. After a brief conversation, Amy turned back, gesturing excitedly for Thalissa to join her.

Curious but cautious, Thalissa joined Amy, and together they walked through the slowly opening gates into the Golden Oasis. They were escorted by the Eternal Treant Sentinels toward the heart of the territory.

"What did you say to them?" Thalissa asked quietly.

"Not much. We are allowed in because the lord of this oasis granted us passage," Amy replied.

"I just hope this lord is kind and just!" Thalissa said. If only treants inhabited this oasis, she would be sure. But the presence of undead dragons made her uncertain.

It was well-known that treants, like natural elves, belonged to the good and lawful faction. In contrast, undead creatures were of the evil and chaotic faction. The two factions were fundamentally opposed and rarely coexisted.

Yet here, in this oasis, both undead dragons and treants existed together, shaking her worldview.

As they walked, they saw many sandfolk and desert coyotes helping them transport wood and stone.

Thalissa's curiosity and confusion only deepened.