Lucis spend the next week improving the underwater cave creating a proper air flow using bamboo. He connect a dozen bamboo as pipe to the main hall and added enchantment of air vacuum on the top to take air in the cave. He add another bamboo pipe that goes straight to the 39 floor to discharge air with air vacuum from the bottom.
He spend the whole week making the bamboo pipe while studying various spell, rune and array making. He's not the best but he can do the basic and simple enchantment.
From the water at the bottom, Lucis swim a couple meter north then going up and he arrived at the surface inside the cave, he stand in open area about 30 meter wide box with a two path into the real cave. One is a small hidden door that look like a pile of big rock and another is a hidden stairs climbing to the top floor.
He designed it very careful and calculate everything in term of defense and escape path. if someone enter the cave, finding the two entrance is next to impossible. but even so, the energy flow there is already powerful enough to tempted anyone that reach the entrance area.
He also want to add devine sense blocking array to cover everything but he doesn't have the resources or equipment needed. What a sad life he's living currently.
After checking the plant and see that he still need to wait a bit more before it can be used, he returned to his cave hall and began expanding the first floor adding 3 more room for future use.
He want to use these 3 room as garden for herb and poisonous plants. he created basic 10 meter wide each room until he's ready for plantation.
When hes on the 3rd room, he hit something harder than the stone one the first room he made previously.
He frowned and squat examination the hard material he just hit. It's almost damaging his sword. The sounds especially frightening because he's in the cave. it's vibrating and loud.
Lucis squat down and examine what he just hit. he have to use physical touch because the room is too dark. his devine sense only confirm the shape and not the real material.
After a couple of minutes, he suddenly jump up and smile widely and even laughing a little. He found a black iron ore vein. the ore is shattered after being hit by his Solidus sword.
"finally." he shout and quickly use his sword hacking around the ore widening the area. he completely disregard his Solidus sword week being.
"a good start. I wonder how many are there in here." he start digging faster. The ore vein going downward and start getting bigger and bigger. The amount he can mine with just the area he dig already enough to make hundreds of similar solidus sword.
He quickly calm his mine, fall in deep thought when he suddenly ran back to the East Main hall in the second room he dug. The size is still barely 10 meter wide.
He start hacking like crazy transforming the small room into something big, I mean huge. it look like a dynamites have blow the place out.
In his excitement, he almost dug out to the size of the main hall before he finally snap out of it and stop.
Lucis examining his surrounding and lost in his own thought for a couple of minutes before he snap out back.
He ran back and forth to the surface cleaning all the stone on the newly made room. He didn't even bother about day and night outside as he running around like crazy.
"I call this room, treasure room!" he put his hand on his hips and laugh out loud. The room is big with a couple of stone shelf and table. Not the best but acceptable.
He ran back to the 3rd room on the west and began mining the black iron ore and pile it up in the treasure room that look like a blasted room than a treasure room.
"that's not right." he stop after he mine half of the black iron he dug so far.
"I need to turn this into ingot first before putting this in the treasure room." he slam his forehead. Feels like he just wasting time for no reason. The ore he brought is piling up at the corner of the room and if one not careful, they might have mistaken it as leftover stone dug out from that very cave.
Lucis can turn this black iron ore to ingot easily if he already have foundation with the strong essence fire. Now, he still need firewood if he want to melt it down and he doesn't want to burn wood in this cave. The smoke would attract a lot if attention.
After weighting his choice, he stop mining and put the process for the iron ore at the back of his mind. It's not like the ore going anywhere right?
Lucis went to the back of the cave and start expanding the hall further to the north and leave the stairs at the center of the hall. The hall look like it's freshly blown up. He's planning everything on impulse.
The hall become 90 meters height and 150 meter long and retain the same wide because he already made room on both side. It truly is a huge hall. Sadly, he didn't dig anything this time.
With that, 2 week wasted with just expanding the cave and little to never cultivating. Fortunately,the plant he wait is just at the right time to be harvest.
He spend another week very careful with his plan and do some extra precautions in case the brewing is a failure.
3 week without talking to anyone except to Dini and elder Dun but even them, they rarely even saw him. Everyone in the village is at ease with the supplies they got and some even forgot about Lucis existence entirely.
Finally, after all the planning, he start brewing the foundation potion on the 39 floor. No one bothering him in here and he can do everything without worry.
Luck is on his side. He spend 3 days brewing potion inside the cave without even once return to the surface. Out of the 10 portion, 4 failure and 6 success and now he doesn't have any material left. he either succeed or forced to travel further in the endless mountain to search more plants.
On the 4 day. He came out from his seclusion breathing some fresh air. He stay the whole day walking around the forest appreciating the nature and looking for dangerous beast track.
He even saw this one scary looking girl with a lot of scar picking up wild plants. From the look of it,he only pick something that can be eaten. Lucis want to say something to her but he doesn't want to add anything more in his mind at the moment.
The process of building one foundation is a dangerous task and he need to have a calm and clear mind.
He walk near the entrance of the village looking at the villager from afar. After some time, he let out a small smile. The villagers look at lot more lively now compare to how gloomy when he first arrived.
Kid running around without worry and some people similar his age socializing more than before. They look a lot less worry and carefree. There's even some flirting around trying to increase their wife collection at home.
If he's still on earth, this is the kind of place he want to spend the rest of his lifespan.
Luna and Yina is the most popular at the moment after the incident during the trade. People looking at them with respect and began seeking advice from them like they're some kind of elder or something.
During the 3 week that Lucis building his cave, he sometimes caught some wild beast and gave it to elder Dun or Boris secretly.
overtime, Lucis heard less and less complaint from Elder Dun. Overall, Lucis doesn't have anything to worry and can proceed for his foundation building in peace.