So, Velantas city is made of six towers in a circle around the seventh one. The populace lives on bridges between and on these six circle towers, while the seventh can be used on the inside as well. How do they fix the sewers then?

The bridge-towns simply release it into the lake as it is, but what about the towns twirled around the towers? The answer is: they use the inside of the tower as the sewer. Why? Because the ground would turn too unstable if they dug out a sewer system. 

In other words, I think I may have bitten more than what I agreed on...

---

"...and therefore, try to find the root of the rat problem. Traveling through the whole system is presumed to take a month due to the lack of light, the rat monsters, and having to restock on provisions, so be careful down there."

After saying his bit, the old sewer-working old man left to fetch the keys. For what? For the massive steel doors which act the entrance to the sewers! What are they keeping down there to need such stupid-solid doors?!

Crap, the two goons are looking at me. Stop starring at me like that! I didn't know a few rats would take so long to exterminate! 

It didn't take long before the worker returned with the keys. Heavy sounds came from the door as it opened up. Seriously, what do they have in there?

"Here are the keys to open the doors from the inside. Make sure not to lose them." - Worker old man

I was given the keyset of keys... which I imminently threw into the Storage. Not gonna lose those.

After the doors closed with the same, heavy sounds, the goons didn't waste any time complaining. I ignored the sound with a:

"Stop wasting more time complaining and start working."

They shut up hearing that, probably because they too didn't want to stay in these sewers for too long, if not at all.

The sewer tunnels are divided into two types. The first is the entrance type, as I've named them, which is a simple tunnel connected to the entrances to the surface.

The second type is the norm, the waterway tunnels. These are the norm. Just like the name suggests, these are tunnels that have a large waterway in the middle of the tunnel with pathways on the sides and a few grid-bridges connecting each side here and there. 

There were some problems, such as Ice-guy not being able to see in the dark, so we had to use a torch. Or so I thought, but then I remembered I had the spell version of the [Night Vision] skill, so I used that on Ice-guy. Almost forgot about that one...

The fallen angel was alright. Seems like that [Celestial's Sight] skill shares effects with several sight-related skills, such as [Night Vision] and [Magic Power Perception]. I-it's still not enough to compete with [Magic Sight]!

A problem we didn't encounter was that regarding space. You know Ice-guy's using a halberd? Turns out the sewer tunnels are big enough to let him swing the big thing around, no problem.

The flip-side is, we can't use my idea regarding his [Ice Wall] to block the tunnel. You know, in case a tidal wave of rats come charging? 

Despite the differences this whole situation had with my plans, we still advanced into the tunnels. I deployed 3 Skeleton Rats for 35 Materials each, so they would be able to use my [Auto-Mapping] skill. They also got [Presence Perception] in addition to their [Lifeforce Perception], so they should not get caught by something hidden in here.

Using more Materials for an undead creation allows me to enhance the undead's stats, or add one of my own skills to the undead. In this case, I created the Rats so they could map the area, so the extra Material cost is well worth it.

However, despite my diligent act of converting the corpses that I can't eat, I'm still only at 132 Materials! Way too little to make the army of undead rats I want. Mapping would be so easy if that was possible...

It's been an hour since we first entered the sewers, but we've yet to encounter any enemy rats. No one wanna face uuuus~...

Damn those wimpy rats. They fled with their tails between their legs before we even saw them! I need Materiaaaaals!!

Ice-guy and the fallen angel's not complaining at least. They used some magical anti-smell items to withstand the sewer smell.

Ice-guy in particular is happy with the current situation. He bought the skill version after experiencing the effects of Night Vision, and his skill level just goes up without him even needing to lift a finger. And he only needed a single Skill Point for it...

M-moving on! Charge, charge, CHARGE!!

Huh, Rat #3 discovered something in his tunnel. [Auto-Mapping] got this nice feature of showing other living creatures you are aware of when it reached skill Lv.15. It's no worth for me normally, but in conjure with the Rat scouts, this effect shows its true worth!!

Let's see, one, two..., 10..., 100? Uh-oh.

E-e-escape #3, ruuun! Retreat, retreat, RETREAT!!!

#3 hightailed it outta there... but he's leading the monster-army with him! Oh, crap.

"Battle positions." - Garami

Ice-guy and the fallen angel looked at me in confusion but started to prepare themselves when they saw me setting up spiderweb on spiderweb in the tunnel that #3 should emerge from.

Ku-ku-ku. I never got the chance to show it off in the Water-Knot, but this instant-web technique is through the use of [Create Trap]. With it, I get a helping hand when creating traps, plus I can instantly create any trap I've made before, as long as I save said trap in the Recipe list of the skill.

And what is my most used trap ever? Webs! 

But still, the webs aren't placed with the thought of balance accounted. They're not big enough to cover the whole tunnel, so only one side can be attached to a wall. They're still holding on, but they're less solid than the webs I'm used to. Better cover that up with more webs.

#3 arrived not long after the sixth web was in place, running through the small gaps I'd created in the webs at the bottom, before closing it. The sound of many footsteps came from the tunnel #3 arrived from...

Wait, isn't this a little too many from the sound of it? Also, they do not sound like not your garden-variant rat... or sewer-variant either. The footsteps are too heavy for that.

And not too soon arrived the answer to my question: humanoid rat-people. 

"Ratmens!?" - Noire

I thought it would be something like that. They look like a rat and a goblin had a child. Lots of children... or rather, too many? There are tens of them already insight, and more are coming from the tunnel.

You would figure that I would freak out over the crazy amount of rats, but they all got caught in the webs. Once the first line filled the web, the second one tried to push on in blind rage, which broke loose the first web, only for the whole deal to be caught with the second web.

This is not good. They're breaching all the perimeters!! 

I hurriedly started to throw out more threads... when did I get so fast with them? 

I Identified my status while throwing threads and saw that I had various status-up buffs on me. What gives?

Fallen angel! Was that you? Good job! Heck, when did she start throwing them out? My thread working is so efficient now that it's scaring even me. Damn, those buffs are efficient. But the ratmen are still pushing on!

And before I noticed, some of the rats had started to swim upstream to bypass the web barrier. That's unfair! I've got no waterproof threads!

Then, Ice-guy came to the rescue. He slammed the hammer-part of the halberd into the waterway, and with that, the whole thing froze over, wait, it froze over?! 

Only the part starting from the third web and a few meters after the final line of defense, but the rats that were swimming in that area are frozen solid. 

Ice attribute skills are too OP when used in the water...

Seems like the waterway doesn't get clogged due to the massive block of ice in the middle of it.

The old worker-guy said something about there being some small channels in the walls of the waterway that allows the sewer water to run through in case the main way gets blocked.

The rats started to climb on top of the ice block, but it's too slippery for them to travel far enough. Those who manage to reach the web-free area gets to meet with Ice-guy's halberd. 

But man, Ice-guy's ruthless with that thing. The halberd weapon has three different weapons attached to the end, with Ice-guy's being an ax, a spear, and a hammer. And he's using all parts equally well to slash, stab, and crush the ratmen. I would have pitied them if they weren't attacking us.

It didn't take long for the ratmens to start ignoring the thread-and-rat-barricade and focus more on crossing the iceblock. That means I can help on the frontline instead of this tedious barricade-working! Heck, can we even remove this stuff afterward? This side of the tunnel's turned completely white, with just a few thuds of fur sticking out here and there. 

But, how am I supposed to assist? Ice-guy needs as much space as possible to swing that halberd of his, and there's not much space that needs to be guarded either. The fallen angel just needs to give a few support spells here and there when the old one's about to expire, but all I can use is Night Vision.

Hmm... I think I got an idea.

I climbed up to the roof above the waterway with my threads, for then attaching my feet to the roof with some sticky threads. 

While upside-down, I produced a durable thread that could act as a whip. Then, I drew out the new dagger of mine... whoaaaa... that's some dark blade right there...

Crap, I got sidetracked. Anyway, I bound the Carnwennan to the end of the whip-thread, then I started to spin the improvised flail a little, before throwing it at the unsuspecting ratman-army. The blade struck the rat right in their head.

Headshot! Insta-kill!

Poor lad. Especially since I used the Aura, Mana Burst, and even [Poison Coating] on that blade...

Let's keep this going!!

---

*Urp*, who the heck came up with the spider-dangling idea? I'm gonna kill 'em...

So yeah, staying upside down all that time was NOT a good idea. All the blood went to my head. Urgh...

But, we got rid of all the rats. I mean, it was only a question of time before we got rid of them all. My improved chain-and-sickle, or rather, thread-and-dagger, got rid of most of the ratmens before they could get close to Ice-guy.

They sometimes tried to cut the thread with the old-looking swords they had, so I had to be careful about that... until I figured out that I could use [Parry] Arts with my improved weapon. Then there were some magician-types there who tried to blast me off the roof, but the Magic Guard Art of the [Guard] skill blocked them. This must have been the first fight I've ever used [Guard] so much...

Ice-guy didn't use any fancy moves to save stamina, but he still pummeled every ratman that got within his range. One of them even had a decent metal shield, but Ice-guy simply used some trusting Art and broke through it. Simple, but reliable.

Even the fallen angel got to contribute with something else than just support. While the buffs were up and running, she shot Holy Magic spells at the ratmen whenever she got the chance. She used up quite the amount of MP Potions... should I have her focus on getting the [Overeater]/[Golden Ratio] combo that I have? 

Both Ice-guy and the fallen angel's barely able to move from the exhaustion. We've recovered with potions and healing spells, but the mental exhaustion is a different story, so we're taking a break now. I'm all for a break myself...

I ordered #1 and #2 to return while having #3 patrol around here and warn us for any monsters that may try to ambush us. I also made a #4 and #5 with the corpses I converted to help him. 

Now that's outta the way, let's use the break to look at the rewards.

Weak! The rats are too weak! That many, and I only got 4 level-ups!

Ice-guy got only three levels, and the fallen angel two. They also got the Legion of One title, plus the Vermin Bane title, so that's two more Skill Points for them after the Champion cheat.

Ice-guy also got the Beast Slayer and Rodent Slayer. That'll help his stamina and resistance even if just a little. 

The fallen angel got the Magic Arts User title due to her spell-spamming. The MP-reduction effect is great for a spell caster like her.

The clean-up was just as horrible as the fight itself. Ratmen doesn't have any particular good materials, so I was allowed to convert all of them. It was a paaain. But [Necromantic Rite] reached Lv.9 from this. A good trade-off?

The total amount of ratmens were:

• 212 Ratmen
• 22 Ratmen Swordsmen
• 18 Ratmen Spearsmen
• 8 Ratmen Brawlers
• 4 Ratmen Pugilists
• 2 Ratmen Rage Warriors
• 1 Ratman Archer
• 12 Ratmen Shield Warriors
• 1 Ratman Shaman
• 5 Ratmen Earth Mage
• 1 Ratman Wind Mage
• 5 Ratmen Water Mages
• 2 Ratmen Dark Mages
• 16 Ratmen Thieves
• 2 Ratmen Rogues
• 1 Ratman Hunter

That's a lot. Good thing that the ID Card counts the monsters we kill or this would have been impossible. Not to mention that [Chaotic Concurrence] has such a low cooldown period when used with Rite. Even better than I could convert those who were in the iceblock or the heap of webs. Those in the webs were killed with Holy- and Darkness magic by the way.

Converted to undead Materials, the regular F-rank Ratmens gave 2 Materials for each individual, meaning I got 424 Materials just from them! Add the E-rank Class Ratmens that give 4 for each, and that's a total of 824 Materials obtained from this one fight! Yahoo!!

...But seriously, looking at the list, we were damn lucky with our opponents. If a Ratman Fire Mage or something had snuck in, things may have ended differently. My threads are weak to fire.

Then there's the fear of some other monster getting attracted by the ruckus we made. I received more damage from the anxiousness of something like an alligator monster suddenly appearing than what I got from the rats.

But, we're fine! All okay! The work's not done though.

"Hey, can we not return? We defeated the rats..." - Noire

Even if not everyone understands that!

"The Quest was to find the source of the rat outbreak, not defeat the Ratmen themselves." - Alf

So said Ice-guy, while still a little listless......?

Crap. #2 got done in. So fast, it never managed to give me any info about the assailant.

I ordered #1 to return to the area we're resting at while dismissing #3 and summoned two Skeleton Shield Warriors with extra materials for a power boost.

"What's up?" - Alf

"Gotta check on something. Be ready for a quick escape." - Garami

I left the Shield Warriors behind as guards (even if they're weaker than Ice-guy) and went off to the area where #2 breath... where #2 stopped living... stopped un-living... you get what I mean!

It didn't take much time to arrive at the scene of the crime. #2 had been killed (let's go for that) in a large area where many of the tunnels converge. I kept my stealth-skills running at high, hoping I wouldn't be caught off-guard like #2.

It must be the middle of the tower... or so I say, but we've not ventured so far in to reach the middle.

Anyway, all the tunnels ended in a huge area that looks like an inverse tower inside the tower. Or rather, like those big malls with a free open space between the floors? Where one can see the bottom even from the top floor?

The waterways continued down the edge, turning into waterfalls. It would be a pretty sight... if it wasn't sewer water. I wish I had taken one of those smell-removing magic items as well instead of toughing it out.

However, the smell isn't the real problem here.

In the airspace was countless of thin threads. Threads forming something I know all too well. This waterfall area has been turned into a spider's hive. And what a spider it is.

A jet-black body with white markings picturing skulls on its back, the top of its head, and the knees of each leg. It's bigger than an ox, and its head has three faces, similar to an Ashura. 

......Mhm. Okay.

Tactical Retreaaaat!!