Swimming in that narrow tunnel took Rino a long while and his flowy cape often got stuck on some rocks. Thankfully, it was tear-resistant.

Like how he ended up in the lagoon, Rino fell headfirst at the sudden drop and flailed ungallantly before landing with a huge splash. The water here was much shallower than the lagoon, and the height of the fall was a lot shorter than that cliff.

Rino paddled out of the small pool and dragged himself up to the cave floor while trying to get the water out of his skull's cavity. He opened his jaw, and the water came flowing out effortlessly, although that feeling was still very odd.

The squelching sound of water in his boots again made Rino sigh internally. He would resolve that later. For now, Rino took a look around with the help of dark vision. There was no longer any lighting here. However, Rino could tell that there was heat in this area. 

It was a no-brainer where he should be heading to now that there was only one path. Rino wasn't afraid of traps in this place because it should be a place that the dwarves frequented with the signs of mining activities. The old tracks that the minecarts created could be seen on the floor, and Rino followed them deeper into the cave.

As he followed the ruts, Rino noticed the interesting patterns on the cave wall. Unlike other cave structures that were mined out of naturally forming, there was a lack of limestone, and the wall's surface was very smooth. There were lines along the wall that remained consistent as if there was water running through this tunnel for many years. The shape of this tunnel was also inconsistent, like a worm had dug it.

At first, Rino thought this was just the marks created by mining. However, he soon came to realise this was naturally occurring. It might not be in recent years, but the tunnel he stood in was definitely full of lava many years ago. He read about it once but did not think it was important to know until now. Rino thanked his boredom in the previous life as he devoured books of all kinds during his home imprisonment period.

Lava caves were pockets created after the lava flowed through it and cooled along the sides of the ground, forming part of the tunnel's walls and ceilings. They were often fragile and could cave in at any part. The heat here was probably from lava activity laying dormant. The hot spring water was also originating from sleeping lava activity underneath the mountains.

This would explain more things now. Rino stopped for a while to admire nature's creation. The dwarves did not do much to this structure except to support it with beams so that it would not collapse inwards, but the lich had a feeling he knew where they were going with this.

As soon as the rut trails ended, Rino looked up to find himself in a cavern bigger than anything in his imaginations. They were so deep underground, but Rino could see even without his dark vision ability.

The ceiling stretched as tall as five hemp trees and could fit all of the world tree inside here if Rino grew one. Unfortunately, that space was taken up by an enormous crystal that pulsed lightly as if it were breathing quietly in a deep slumber. The crystal would slowly change colours as it throbbed, and Rino walked closer towards it in a trance. It stretched all the way from the broad base on the ground to the ceiling of the cavern. Rino squinted and concluded that it was still growing even if it grew only a few centimetres in a year.

A living crystal within this mine would explain the need for those deadly traps and obvious distractions. The dwarves were guarding the guardian of their mines. The pulsing crystal did not just emit mana. Rino would consider this closer to an unawakened fae.

Living crystals were often depicted in myths, but Rino never found any in his previous world. Any living crystals his previous world had must have been destroyed by greedy profit hunters.

These crystals have been around for thousands of years and accumulated spiritual energy that was different from mana energy stemming from life. It was a soul of its own creation over many years of cultivation as a crystal. Huge living crystals like this were unheard of. Small living crystals could sell for a fortune because they were protectors of the owner's family for generations, warding evil and bringing good fortune. Their powers would die eventually if they were not charged sufficiently or used too often. Rino never saw one or knew anybody who owned a living crystal, big or small, in his previous life.

Now, he could not help but wonder why anyone would want to destroy such a beautiful thing. The living crystal in this dwarven mine was the owner of every rock, mineral, ore and crystal. The dwarves must have worshipped it like a god and went through so much to keep it safe. The peace that this volcanic mountain had must be the crystal's doing. Rino had no idea if living crystals could actually suppress a volcano or calm its rage. However, he did not want to test the theory and risk having everything in Town Zera blown up when he was just getting started.

Surrounding the living crystal was a litter of crystals, rocks and ores. Rino recognised some of them, and the shiniest of them all had to be quartz. They sparkled in tune with the living crystal's colour change.

Examining the walls, Rino was quick to notice a familiar colour. Walking over and brushing the white surface, Rino confirmed that this was quartz and the little yellow sparkles were gold!

Sections of the wall had been mined previously, but there was plenty of where that came from. Rino marvelled at the cave for the next fifteen minutes before doing the logical thing.

Although he wasn't going to mine the living crystal, the same could not be said for the other crystals conveniently located in the same cavern as it. He had a daily quest to complete, and Rino did not wish to mine crystals underwater while fighting against the impossible current. Hence, he apologised to the crystals in this area and retrieved the pickaxes from his shadow sack.

Clink! Clank!

While working quickly and shopping for the best quality crystals in the cave, Rino quickly harvested sixteen different types of crystals and saw his daily quest mark itself completed in record speed.

Ping!

===

Daily Quest #27 (complete)

Objective: Mine 16 types of unique gems

Time Limit: 16 Days

16/16 unique gemstones

Tutorial here.

Reward: Master Crafter Skill

Claim your reward here.

Penalty: Deduct 24 hours of sleep upon failure and [Curse of Overtime] until quest is forcefully completed.

===

Before Rino knew it, he had mined amethyst, sapphire, jade, opal, tourmaline, ruby, emerald, diamond, quartz, topaz, tiger eye, malachite, onyx, citrine, jasper and moonstone. These were the crystals he often used in his alchemy experiments in his previous life because of how durable they were.

Claiming his reward, Rino looked at the living crystal and made up his mind. Initially, he thought of adding them to the powerful array in the dwarves' secret artefact vault. However, this living crystal was more precious and needed better protection than those weapons.

Laying the crystals in order, something Rino was very familiar with, the lich used coal to draw out a complex magic circle on the floor around the fat living crystal. The circle took almost an hour to be completed because of the level of details Rino wanted. However, by the end of it, he was satisfied.

The rune circle glowed as Rino chanted his long spell, pouring mana into it and gently weaving the living crystal into the circle's protection while feeling out for the established mana web array in this cave using the living crystal's consciousness. They made a connection to the mana web array, and once Rino introduced it to the Genesis Tree, who introduced it to the Ghost Cypress and World Tree, a brilliant flash of white glowed from the living crystal.

Outside of the cave, Acht looked up at the sky and noticed that the eternal night barrier only became darker, and the town was shrouded in a light mist, obscuring vision. Outside, a thick fog covered Town Zera's location, and the borders expanded for the next few miles all the way to the forest that Rino found himself in just yesterday.

Rino continued to mutter his spell and ignored the stabbing pain in his eyes caused by the bright light from the living crystal. There was one area that he needed to fortify, and that was the artefact vault.

There was no greater mana amplifier than a living crystal, and Rino was amazed by just how much stronger Town Zera's defences had become. The border he wanted to create was established. The enchantment spells and layers he wanted to cast over his town were now made possible thanks to the living crystal in the heart of this mine. Rino bowed humbly and thanked the living crystal for its assistance.

Pulsing in response with a warm colour, the living crystal replied, and Rino took his leave. He finally had a reliable guardian watching over Town Zera and protecting it from the silence.