Looking at the Island, Xin feels the need to start so that he can take the girls here and start their own organization.
Xin then starts to expand the whole Island, he makes it half of bigger than the actual size of the Marine Academy school.
He made the foundation that even the powerful cannon can break, he layers different hard rock and limestone below the whole Island.
After he is done, the Island is now the size of a small village, but this is pretty empty because the whole ground is full of coral from under the sea.
Xin then dive under the ocean floor to collect building materials, and what he discovers under is a large amount of Seastone.
Seastone, called Sea-Prism Stone is a naturally occurring (though apparently rare) substance that can drain the energy of Devil Fruit users to the point where they can't consciously control their powers.
Dr. Vegapunk has invented revolutionary ways to use this rare substance. The Marines appear to have vast quantities of it, using it for jail cells, handcuffs, weapons, and the bottoms of battleships.
Of course, Seastone not only can drain the energy of the Devil Fruit user, it's also good building materials for his unique hardness.
And there's also a good use for this, it can use a self-defense mechanism in case a devil fruit user suddenly invades the Guild.
Imagine a whole building made from Seastone, that makes everyone jaw drop on the ground just looking on it.
Of course, he will also make a simple reception area for Devil Fruit users or maybe make the whole reception area Seastone free.
After mining in the depth of the sea, Xin starts to compress all the materials that he gets using magic, he compresses all of it using hsi full force and magic compressor that he invented for this project.
And the result? Well, a block of rock that is harder than metal, heavier than gold and durable than platinum.
The mixture of Seashell, Seastone, Stalagmite and ground Seakins bone that he got underwater made a white brick that can be used as a weapon if needed.
Guil's main headquarters resided in an imposing building consisting of three floors and incorporating several architectural styles: it took on a shape reminiscent of a pagoda, with each floor being smaller than the one below it and sitting on the latter's roof.
The roofs also bore great resemblance to those of real pagoda, consisting of extremely long, arched tiles lined up one after the other and possessing simple curved protrusions jutting upwards on the building's angles.
On the highest roof, topping the summit of the building, sat a simple, round and pointed dome, highly reminiscent of those seen on Arabian buildings, which bore a flag on its point.
The roof below the one with the dome, the middle one, housed a large banner with Fairy Tail's symbol on it, held up by a pair of vertical poles.
The building's large entrance was again Arabian in design, with its shape being reminiscent of that of the dome on the summit, and above it was the guild's Logo going to place..
Stylized square shapes were also visible on the frames of the numerous, large pentagonal windows located on each floor, with the top floor housing smaller, arched windows partially covered by banners.
The inside of the building highly resembles a small restaurant or pub, mainly constructed of wood. The room possesses a stone floor, and several small, round tables are scattered across it, paired with some chairs.
In the right side of the room is a bar counter, complete with a sink and several bottles, which has a wooden platform in front of it, with some more tables and chairs sitting on it, plus some round bar stools by the counter.
Behind it is a staircase, with its landing sitting on the only structure of bricks in the inner part of the building, a massive, rectangular column. Leaning against the walls are some bookshelves packed full of books, and at the entrance's sides are a pair of plants kept in jars.
Some lamps are attached to the pillars adjacent to the walls; one of such walls is covered in a variety of frames, of different sizes and shapes, seemingly housing pictures.
Of course, all the woods used are from Fishman Island and O'hara's excess Adam treasure wood.
If someone calculates the cost of the building materials, they will faint from the value of the whole building.
Even Xin feels that he uses too much of her own resources just to build this simple but elegant building.
Well the result is excellent, even Whitebeard using his Devil Fruit here will only shake the whole Island but it will cause no damage on it.
After making the whole building for the whole day, Xin then starts to engrave different Magic Runes and Magic circles all over.
Making the whole building indestructible and self-repair System.
The guild is not only a base for the new organization but also an indestructible fortress that no one can destroy, of course, it's different if someone tries to submerge the whole island under the sea.
Next day, Xin starts to make a different facility like Training Room, Training Ground, Guild Library, Arena, Kitchen, and even the Trial Tower for anyone who wants to advance in rank.
The only noticeable is the Tower that Xin made not to go up but to go down, each level has different difficulties like the one he made in the training camp.
But this time he made a bunch of puppets with different strengths, if you finish the current level you will advance to the next level and your rank will go up.
Of course that for the future, there's still no one qualified to sue it except for the girls and the people he invites to join.
He did it for the whole week just to complete it, he did n't eat or sleep, he finished the rune engraving and replenished all necessary equipment inside.
Even the Guild Library is full of books that Xin wrote based on his experience. Of course, there's also books for Reiatsu, Nen, and Chakra, there are also books of Magic.
But the only one who can read it is the only one who can pay the right amount of Guild Contribution.
The next day an unknown ship suddenly arrives on Guild Base, It Hancock with her crew who just arrive after hearing that Xin finally gets the Island for his Guild.
"It's beautiful here, I did not expect that the Elders would give something like this to Xin," Marigold said.
"Let's go, and see what Xin is doing right now," Hancock walks inside.
After a few minutes of walking, they see Xin, not inside of the guild but in the farm fluid cover with the first while planting vegetables.
"You come to visit? Sit for the meantime, let me fish my work first," Xin said without looking at them.
Hancock walked to the bench below the towering tree and sat down, she looked attentive to Xin while planting, today she discovered a new thing from Xin.
She felt that her time visiting her did not waste at all.