Water 7 was a man-made island so it didn't have its own magnetic field. There were no direct log pose to the island, people had to board sea trains from nearby cities to reach there. And one of such city was Thistle city in Sukia island, it was in close proximity to city of water. The main interisland transportation medium was a sea train. Mihawk being an experienced wanderer, he had already planned a route. He had a log pose of Sukia Island, and after they reached Thistle city, they would also have to board a sea train to arrive at the destination.
Traveling in the sea for two days, the duo of Vash and Mihawk finally arrived at the island. It was the port city named Holaer, and Thistle city was at the other side of the island.
"Why don't we go directly there along the coast??" Vash asked.
"I have some business inland." Mihawk replied.
"Oh... Okay." Said Vash and made the boat float with Supreme Kings Haki.
"So what do you need in this island??" Vash asked again.
"We're going the place called Indigo Valley, It's located at the center of this landmass." Mihawk replied.
"And what's so special about this place??" Vash asked.
"...You'll see." Mihawk replied and didn't say anymore about it.
"Hmph..." Vash just snorted.
The duo trekked their way through the island and arrived before a valley.
"Indigo Valley... The name fits the place." Vash said. He could see plants with various colored flowers blooming in the warm sunlight.
Mihawk walked following a small stream and its source was deep inside the gorge. So the duo meandered through uneven terrain like they were choosing a picnic spot.
Vash observed the lack of organisms on the way as they travelled. Beautiful indigo plants were left behind and only ugly ferns grew out the ground.
"It's boring here. So can you tell me now where are we going?" Vash asked, he was walking mundanely in dirt and got bored easily.
"We are going underworld." Mihawk replied in short words.
"The hell man... Are you so eager to die?? If not, going to hell is not a good idea. And besides, does underworld even exist??" Vash exclaimed.
"Apparently, Underworld is real. There are some records of people returning from there, after they had died. They described it as a chilly place, and it's hard for spirits to survive there." Mihawk explained.
"Are you sure you aren't spouting bullshit?? How can people come back to life? Oh... Let me guess, it must be some kind of equally bullshit devil fruit ability. Isn't it?" Vash said.
"Hmm... Revive-Revive fruit. It's a useless fruit when a person is alive, but it can revive a user once after their death." Mihawk said.
"So let me ask again... Why are you suddenly interested in Underworld??" Vash said.
"Just curious... I always thought that death signifies end of everything. The body rots, consciousness blanks out and spirit scatters in the void, this is true death. But the souls of the dead go to the afterlife, and I can't wrap my mind around it." Mihawk said.
"Hmm... If we go by observable fact, the universe starts with a bang of primordial energy and later condensing into matter. Arrangement of different basic matter gave rise to life. And from complexity of life emerged intelligence. Mental strength and spiritual power are product of extreme intelligence. Lastly, culmination of consciousness, memory and mind power is soul. Body and soul shouldn't survive without each other, so you are saying there is a setup of a system in place, like reincarnation cycle or something." Vash explained with lengthy words.
"You are book smart despite your unlikely appearance." Mihawk said.
"Dude, I have telekinetic powers and I can see future so you could estimate the extent of my intelligence." Vash said with a boast.
"But your actions are dumb sometimes." Mihawk said.
"That's because I don't want to always rely on brain when I can solve everything with brawl." Vash said.
"That's the dumbest line I ever heard." Mihawk said.
"Anyway, Can your own intent affect your future sight, like intending to kill your self and simultaneously using haki to view future? That way, you may get glimpse of underworld through the soul after your future passing." Mihawk asked.
"The future is not set in stone... I can see the most probable future and not the various iterations. That would require more intelligence, processing power and mind energy. And the core of this ability seems to be basic survival instinct, it would let me see the future in which I survived rather than the future in which I'm dead. And of course, if I meet insurmountable opponent all I'll see with the ability would be my death, although I haven't encountered such an opponent. " Vash replied.
"Tch... Your ability is useless... why don't I send you to realm of dead then you tell me scenary through telepathy." Mihawk said.
"Dude... Are you trying to kill me? And I don't even know telepathy, although I could make the technique if I try." Vash said.
"I'm just joking. You'll remain dead if you die. You aren't a revive human." Mihawk said.
"So in the end, why are we here again??" Vash asked.
"I'm getting to it... But first I require your thoughts on the previous subject. You previously claimed to be from different world, didn't you? So could you tell me if any hell like entity was there as well." Mihawk asked.
"Hmm... as far as I knew there wasn't anything similar. And now that I think of it... The life there was probably a result of strings of cosmic coincidence converging together. I felt like a small of part of the universe with its own mind, trying to understand its mysteries." Vash said while thinking.
"So it was different then. I'm no science guy, but I think this whole thing with Underworld is either an elaborate set up by a powerful person or an organization, or it could be simply a universal working. I don't know for sure. So I'm trying to gauge out the possibilities." Mihawk said.
"I have a hunch that the historical events of void century was an unprecedentedly large scale conspiracy. I think that there is a hidden force which nobody knows, and it had been influencing the world, sowing seeds of chaos everywhere." Mihawk further explained.
"And what led you to think so?" Vash asked.
"Everything... Once upon a time, during an adventure I stumbled upon an ancient ruin where I found some lost technology. To tell you the truth I couldn't make out heads or tails of the objects I found there. So I thought why not get some help from the expert." Mihawk said.
"So is that thing here!?" Vash asked.
"Yes, we'll reach there shortly. And I was joking about going to Underworld but the place we are going is not any worse than the hell." Mihawk said.