This is precisely a portal-type nest, seemingly connected to a channel of some sub-level plane. The way this type of nest generates creatures is mostly through summoning, by means of equivalent exchange to summon creatures to serve the summoner. Brand looked at this Light Door, and expertly took out two Secondary Moon Crystals from the Dimension Hole and tossed them in. As expected, soon the Light Vortex brightened up, and then a small head peeked out from inside.

It looked like a little person three inches long, or perhaps a proportionally shrunken maiden, with long curly hair, wearing clothes as thin as cicada wings, glowing all over, without wings, yet able to lightly hover in mid-air.

She surveyed the outside from within the vortex, then suddenly flew to stand before Brand and the others, and greeted respectfully, "Hello, Lord." Her voice was thin, with a somewhat strange accent, like a foreigner articulately speaking Kruz Language.

While speaking, the maiden curiously observed everyone, yet did not seem afraid. 𝗳𝗿𝐞𝕖𝘄𝗲𝕓𝗻𝚘𝚟𝕖𝐥.𝚌𝕠𝕞

"The Lord she refers to is the owner of this Magic Territory, somewhat akin to your human Lords, but different. To magic creatures, only those who possess strength are naturally deemed Lords; they do not acknowledge titles based on reputation," Medisha explained to Qian and Romantic at the side.

"Oh." Romantic uttered an 'oh' sound, it's unclear whether she understood.

But Brand nodded, unlike Qian and others, his past experiences in the game made him familiar with these magic creatures, so he directly asked, "What is your name, what type of creature are you, and what abilities do you have?"

"I am called Monica." The maiden placed a hand on her chest and chirped away, introducing herself: "We are Light Spirits, commissioned to protect this sacred land, the children of light, our ability is nurturing this World Tree Fortress."

"World Tree Fortress?" Brand furrowed his brows, wondering why the term sounded familiar, as if he had heard it somewhere before. Yet, upon careful recollection, this memory fragment seemed neither entirely from past game experiences nor from stories of myths and legends of this world.

"World Tree Fortress, or, as per your Lord's term, you may call it Valhalla as well, however, Valhalla is actually the name of the second World Tree Fortress; this is the third and final one," Monica replied.

"What second, what third, what exactly is a World Tree Fortress?" Brand couldn't help but ask.

"That, I don't know, Lord. Our knowledge is inherited from the magic power; it's stated this way in memory, this tree is the most basic form of the World Tree Fortress, that's the only thing I know."

Brand nodded again, Monica's statement was not surprising, many pieces of knowledge passed down through bloodlines are just snippets. Though this question was asked casually, he was more concerned with the growth potential of Valhalla.

"Your ability is to nurture this tree, how is it nurtured?"

"Once the World Tree sprouts, it will grow slowly. You can regard us as gardeners who prune its branches and leaves, Lord," Monica answered.

Brand understood: "So you are like the town's inherent workers, this can be understood, right?"

Monica nodded: "That's one way to see it, we can assist Lord in building this city according to your wishes."

"Then what can you build now?"

"Not by myself, Lord, Light Spirits aren't omnipotent! I need more of my kin to cooperate with my work. With one, two, or three Light Spirits, I can assist Lord in constructing the Tree Nest."

"Tree Nest?" Brand didn't understand, he was familiar with Erune Kingdom's construction order, like noble barracks and blacksmith shops, he's seen some high-end buildings, yet had never heard of such a term: "What is that?"

"Tree Nest can cultivate Ancient Tree Roots, they are the basic defense force of the World Tree, with strength roughly at the Silver Peak level, but they cannot leave the World Tree; Lord, you can consider them as a kind of mobile defensive structure, or town guards."

"Furthermore, Tree-men and World Tree are essentially one entity, part of the World Tree, hence they don't need the Magic Pool to provide power. Tree Nest can be constructed in this square or on the upper canopy without occupying the Magic Pool's position," Monica added.