Hajime moved the submarine and the party entered the crack. The pendant's lantern still had around half of its accumulated light, but it had stopped releasing the light. Only the submarine's light was shining inside the dark sea now.
"Umm~, this one had thought this since hearing about the bottom sea ruin, but wouldn't it be impossible for ordinary people to enter this labyrinth without this "submarine" thing?"
"... It's impossible unless one using a strong barrier."
"It will also be impossible if they can't control the air, light, and water current at the same time, eh."
"But, it is necessary to conquer 【Guryuu-en Great Volcano】 to come here, so I think people who are capable of conquering the Great Dungeon are able to enter.
"Maybe we are supposed to use Spatial magic."
Entering deeper on the underwater road, Hajime's party were considering other ways to conquer this dungeon without a submarine. They were impressed by the fantastic entrance, but indeed, once they thought about it normally, unless there were several top class magic users, it was impossible to enter the dungeon. A troublesome point similar to the other Great Dungeons.
With caution, Hajime's party watched the bottom sea through the front crystal.
And at that time,
FwwwOOOOooooosh~!!
"Uwoh!?"
"Nh!"
"Wawah!"
"Kyah!"
"What the—!?"
The side of the submarine suddenly received an impact and immediately, the submarine was thrown towards a direction. Just like the time they were thrown into the magma's swift current, the submarine was turned around and around, but the party had already came up with a countermeasure for it. Using the gravity stone installed at the bottom of the submarine to increase the weight, the party stabilized the it.
"Uh, I don't want to taste this twirling again~."
Shia's face paled as she recalled the time they got swept underground of 【Guryuu-en Great Volcano】, and shook her head to stop recalling it.
"Didn't we recover immediately? I already said it'll be okay from now on. But more importantly, just where does this current led to..."
While smiling wryly at such a Shia, Hajime observed the outside through front crystal. The Green Light stone's light was circulating around the dark cave, letting him pictured the surrounding. From what he could see, the party seemed to have been swept by the current into a huge round cave.
While operating the submarine, Hajime's party advanced by following the current. After a while, the "Farsight stone" installed in the stern caught innumerable objects shining in reddish black.
"They seem to be approaching us... Well, they are most likely demonic beasts clad in reddish black magic power, huh."
"... Shall we?"
When Hajime muttered, Yue, who was sitting by his side, was gathering magic power in her hand, and said in gangster-like tone, but she still looked cute.
"No, let's use weapon here. I also want to confirm their effectiveness."
Hajime operated the gimmick on the back of the submarine. Then, numerous pet-bottle sized torpedoes that had dyed Ancadi's Oasis in red, was launched. Hajime thoroughly painted them so they looked like smiling mischievously sharks.
Because they were inside the swift current, the torpedoes' propulsion could only move them to a small degree, and it resulted with them scattering like sea mines.
The submarine advanced ahead ,and before long, the numerous demonic beasts clad in reddish black magic power with appearance of flying fish entered the cluster of torpedoes.
BOOoOOoooOOoom!!!
Grand explosions generated in succession from behind the submarine and a large amount of bubbles wrapped the group of flying fish-lookalike. Afterwards, the bodies of flying fish-lookalike were tore apart by the impact and the flesh and blood were scattered from inside the appearing bubbles, looking like seaweed thrown into a swift current.
"Yup, it has more power than before. The improvement is a success."
"Uwaah~, Hajime-san. Just now, there was something with eyes of a fish being swept outside."
"Shia, those art actually dead fishes."
"Once again it makes me think the artifacts Hajime-kun made are a foul."
From then on, Hajime's party advanced while easily beating the flying fish-lookalike they frequently encountered.
They advanced without knowing how long it would be.
At that time they began to notice the sense of incompatibility of the unchanging scenery. Hajime's party arrived at a place where the surrounding walls had been randomly destroyed. When they looked carefully, torn heads of flying fish-lookalike were placed between the rock walls with their hollow eyes looking at the sea.