Sen comes to after an indeterminate amount of time aching all over. He groans as he sits up, and tries to look around, to see nothing but blackness. He doesn't bother panicking, his eyes feel fine, so it's extremely unlikely that he's gone blind.
He looks up to where he fell from, and sees a terribly faint light shining through what looks to be tons of rubble. He carefully drags off some rubble that is on top of his legs, wincing as he does so. Nothing feels broken, a testament to how tough the body enhancement skills have made him, but he's definitely bruised and battered.
He carefully stands up, and thinks for a moment on how the hell he's going to get out of here when he can't see. His musing is solved by something simple, the slight movement of air around him. He starts to focus on the sensation of the air, trying to feel around him with his control over wind. He sits there for a few meals and a night of sleep until he can understand the information coming from the air. He can barely feel out rough shapes, but it's enough to see that he's in a tunnel that extends both directions.
He isn't sure which direction to take. While there is wind, it's flowing upwards, likely escaping through some cracks in the rubble covering the hole he fell down. He doesn't want to stay here however, the rubble looming overhead is making him wary. First though, he goes to search for his sword. He isn't good enough with the wind sense to find it, so he simply starts feeling around on the floor, shifting the rubble to find it.
Eventually, he hears a metallic clang, and lets out a breath. He carefully feels around for the handle, and finds from the weight it's his sword rather than that of the man he'd been fighting. He'd gotten some of what feels like blood on his hands while searching, but at least he has his sword now. After a bit more searching, he manages to find his tablet, which has somehow survived the fall.
Unlocking his tablet with his fingerprint, he goes to the mapping function. While it shows where he last was, it has a bright red no connection at the top of the screen, and it doesn't update his location as he moves.
He isn't sure if it will get through, but he sends a short message to everyone in the group, saying simply "I'm alive". He waits for a while, but the tablet simply gives him a "Failed to send" message. Sen lets out a deep sigh.
The soft glow from the tablet, which Sen is seriously impressed by the toughness of, lights the area around him. The walls are stone that is terribly smooth looking. It's like something had simply taken a sphere and hollowed out the rock as it rolled along.
He uses his sword as a crutch as he hobbles along through the tunnel, not sure where he's going. It isn't long until he comes to his first intersection, and on a whim, he takes the left hand path. He continues following it, but after a bit, he notices it seems to be curving downwards. Heading back, he hides his tablet in his backpack so as to not brighten himself up for anything that wants to eat him. While worrying about possible monsters, he takes the other path.
This path also goes downwards, and he grumbles in frustration as he heads back to where he fell to go the only other direction he can go. He eventually reaches the area, and has to focus more on his sense of the air as he walks through the rubble. He gets clear of the rubble soon enough, and follows the tunnel for a while, only for it to start opening up, and Sen begins to hear noises ahead.
Sen slows down, nervous about whatever is ahead, but can't sense anything from this distance, and carefully approaches, controlling the wind to blow towards his back to reduce his smell for whatever is up ahead. When he gets closer, he gets in range of his wind sense, and he notices that whatever they are, they're vaguely humanoid and smaller than an ogre while being larger than an orc. Sen takes a deep breath, this is the only tunnel that isn't heading downwards, and considering their size, they're probably D ranked monsters.
Sen grabs his sword, and uses the energy that has completely regenerated from his walking in the tunnels, slashing in with Weight of the Mountain in the general vicinity of one of the monsters, his wind sense lagging a bit behind. Sen is happy to see that its reaction isn't particularly fast, his estimation that they're D ranked monsters seems to be correct.
He strikes home, his sense for the air allowing him to target the monster's waist well enough. He rips his sword free, and turns to the next one. It seems to be able to sense his general area, but not directly where he is as it strikes at him. Even so, Sen can feel the wind of its claws passage on his skin. Sen takes off the arm that slashed at him before twisting his sword and piercing it through the throat.
Sen's starting to get a bit of a headache from trying to sense things he's fighting, but soldiers on, turning to the last two. They both go to slash at him, and he's forced to take a quick step to the side to avoid them. He thrusts into the torso of one of them, blade held parallel in order to not be slowed too much by the ribs.
The blade is shoved a bit up by the rib it impacts before sliding in between two of them, and Sen rips his sword out of the monsters torso, cutting down the last one as it turns to run. Sen relaxes for a bit, stopping his sensing of the wind, as his head is starting to ache a bit. He ignores the gore around him, only bothering to use the light from the tablet to find a spot not entirely covered in it for a bit of rest. He sits down, looking at the map again. Unfortunately, the no connection showing on the screen won't let him update his location. He goes through the settings, trying to find anything that may help, and is excited when he sees there's an option to enable subterranean paths. He quickly enables it, but no tunnels show up even close to his location. It's as expected, but still annoying.
As his headache subsides, he puts away his tablet, and heads to the direction he'd been going, the ground curving slightly upwards. It continues for a good half a mile, though Sen is moving terribly slowly with how weak his sense with the wind is, and eventually, Sen collapses to his knees. It's a dead end. There's a small pool of water, practically a puddle, but that is all.
He lets out a few curse words that Alice would recognize before looking at the bright side. At least he'll have water. The next few weeks are spent traveling throughout the dark tunnels. He's slowly accruing a map, roughly drawn on his tablet, while wiping out the occasional D ranked monster. He uses the monsters as a food supply, as he's quickly run out of instant meals. He isn't able to cook it, and grimaces every time he's forced to bite into the still raw meat, but he needs to keep up his strength. It tastes odd, terribly bloody, and their meat is so tough he doubts he could even chew it to pieces it without his bone enhancement. It seems to dissolve just fine in his stomach though, as no issues from it crop up.
His only solace is a map on the tablet he's making, which is slowly growing, showing where he's been, and the different tunnels he can take. His mapping continues for a while, until he realizes there's only one path left, and he's been avoiding it. There's a C ranked Ogre in that tunnel, and Sen doesn't want to try hunting a C rank on his own, but it seems he'll have no choice in the matter.
Sen makes sure to rest up the day before, his sleep schedule completely messed up by the lack of light. While he can keep track of the days on his tablet, he's reverted to the thirty hour day/night cycle of Alpha rather than the twenty six hour cycles in the fifth dimension.
Once he wakes up, he heads directly to the ogre. He makes sure the wind is blowing towards him, as the monsters down here have a fantastic sense of smell. He takes a deep breath, getting ready for what's to come. Deciding that his best chance will be a strong attack from stealth, he gets himself in the proper mindset to use Bloody Peak. He charges, his mind filled with images of death, and slashes his sword at where the wind tells him the ogre is.
It cuts deep into the monster, and as Sen rips his sword out, he can feel blood spraying onto his face. He lets out a feral grin, and starts to dodge around the monster, not letting it hit him with its terribly heavy swings. After a bit of dancing around the monster's strikes, it slams the ground with its foot, and Sen is tripped up by a ripple of earth rolling under his feet.
He's forced to use the wind to stay remotely balanced, and then Earth Steps to the side just in time to be missed by a swung palm, sharp claws that Sen can barely sense sliding past him so close he can feel them leaving light scratches on his skin.
He rolls on the ground, the ripple of earth having sent him enough off balance that his Earth Step had pushed him onto his side, and gets back up, the roll having been terribly awkward due to the large sword he is holding.
The monster turns to him one more time, and then collapses. Sen lets out a breath. It seems that he's not doomed quite yet. He drags himself up, and continues past where the monster had been. There's a small turn off to the left, and Sen takes it, finding a small room with a small river flowing through it. It's far better than the puddle he's been using.
He fills up his bottles with as much water as they can hold before drinking his fill and washing himself off as best he can with the light from his tablet's flashlight. He's sure he's still absolutely filthy, but at least he feels slightly cleaner.
Once he's done cleaning off, he leaves the small room, and starts to explore some more. He runs into plenty more D ranked monsters, and every so often he goes back to his small little alcove near the ogre he'd killed in order to clean himself and refill his water supplies.
He knows he's been here for over a month thanks to the tablet, and at this point, his sensing of the air is almost entirely instinctual, Sen as able to use it as well as his normal vision to tell where things are. He's become completely accustomed to the darkness and the different monsters in it. They vary from rats far larger than they should be, to giant bats that could pass as gargoyles if they were made of stone. He's eaten plenty of crystals, even a good amount of C rank ones, though he's sure he'll be falling behind his group if they're still hunting.
Eventually, with his constant exploring, he sees something. Sen blinks. He's actually seeing something! He wants to rush in, but carefully approaches instead, using his wind to see around the curve in the tunnel ahead. The wind has been flowing towards this direction, but Sen hasn't found that to matter much. Wind tends to flow towards the small rivers throughout the tunnels as well.
As he gets closer, he's able to sense something annoying. It's two ogres. While Sen can handle one so long as he gets a sneak attack in, in a fair fight he'll be lucky to get away without any major wounds. He carefully pokes his head past the curve of the tunnel to see what's causing the light, and is absolutely ecstatic.
It looks to be an exit from the tunnel! He can see what looks to be moonlight coming through a small hole at the end of the tunnel. While an ogre won't be able to fit through, Sen is pretty sure he'll be able to.
The issue comes down to the two ogres. If Sen goes for a strike to the neck, he can kill one quickly, but the second will be an issue. He's only not noticed because he's started controlling the air around him, preventing his rather bad smell from leaking. Even with the "baths" he's taken, he hasn't been able to clean his clothes as well as he'd like. Eventually, he decides that the best thing to do is go rest for the day, as he's quite exhausted. He finds a small alcove that nothing large would be able to fit into, and goes to bed with his sword in his hand.
Sen wakes already alert, and notes that there's nothing within the range of his wind sense before relaxing. He slowly crawls his way out of the small alcove and into the tunnel proper, nervous about actually fighting an ogre rather than just ambushing one.
The ambush on the ogre to the right goes off without a hitch, Sen's Bloody Peak cutting halfway through its neck, and Sen tears his sword out with a small flourish to remove a bit of the gunk on the blade, not wanting the gore to get in the way of the cutting edge for the fight to come.
The other ogre roars, and leads in with its stomp that causes a ripple in the ground to flow outwards. Sen can easily sense that with the air by now, and simply hops up to avoid it, before dashing forwards after he's over it, slashing in with his sword.
The blow is blocked by the things arm, and it barely cuts in half an inch. Sen winces. Without using his skills, it will take forever to kill this thing, but the Bloody Peak he had used took half his energy.
He pulls his sword back as the monster swings its hand at him, the claws Sen can clearly sense leading the way. Sen interposes his sword in a way that it cuts into the monster's hand rather than hitting the claws, and it jerks back its hand as it hits the blade.
Sen slashes in with his sword as it jerks back, Sen using Weight of the Mountain aiming at its chest. Unfortunately, it gets its arm in between the two of them, and Sen only injures its arm, cutting down to bone with the skill enhanced strike.
Sen is nearly pulled from his feet as the monster pulls back its arm. He is forced to kick upwards to dislodge his sword, and is slightly off balance as the monster's other arm comes in for another hit. Sen takes a glancing blow, scratches appearing on his chest. Sen steps in, and realizes he's not going to get a better chance to give it a proper blow. He doesn't have enough energy for Bloody Peak, and so simply uses Cutting Squall, slicing into the monster's neck.
He obviously hits something important, but he smiles too early as the ogre's foot slams into him. He's sent flying back, and when he impacts the wall of the tunnel, he sees stars for a bit. It takes him a good few minutes before he's able to stand.
As he gets up, he can feel a pain that's both sharp and dull in his chest, he's clearly fractured some of his ribs, but they're not stabbing into his organs or through his skin, so it's likely just cracks. It's another few minutes before he's able to walk. When he can, he approaches the two corpses, and painfully chops open their chests to get at their crystals.
He looks at them, and downs them without even bothering to wash them off, Ignoring the coppery taste that comes with them. He shambles his way out of the caverns, and is soon outside, looking at the gigantic moon that Alpha doesn't have.
He laughs, ignoring the pain in his chest. He's finally out! It feels like it's a literal weight off his shoulders, standing straighter as he takes out his tablet. He see it have a connection for half a second, but then it disables itself. Sen stares at it for a moment, before realizing that the UFoH knows about their desertion. At least he's stared at the map enough to know where to go to the city they were trying to reach.
Before heading there though, he goes back into the tunnels, going to one of the water sources and filling up his bottles of water before going to sleep.