After most mages had tried pumping the ground full of mana and nutrients, letting the rats eat their fill, it was time to initiate phase two of the plan. While phase one was about gathering the rats, phase two would concentrate on keeping them in place, either if they wake up or during phase three when the plan reaches its final stages.
Since the plan is devised to eradicate as many of the rats as possible it would be troublesome if they can escape their extermination because of a mistake that even rookies won't make when hunting or clearing nests.
Mages with the earth attribute, fighters with piercing or penetrating skills, and anyone else who could collapse and block off the tunnels deep into the ground, were gathered at the outer edge of the circle. Meanwhile, everyone else left the circular area and started grabbing buckets before heading to the redirected river. The buckets were large enough to fit a decent amount of water and when filled with water, heavy enough that people would likely go to bed feeling like their arms are about to fall off.
In order to not let all the water drain out into the wasteland, the river had been diverted away from the forest and toward the campsite, partially to make it easier for them to get water for cooking but also because it had proven effective against the rats when used in various ways. The river continued stretching along the wasteland without actually getting too close since while the humans are busy exterminating the rats in one area, rats in another might continue to extend the wasteland and drain away the water.
A few earth and water attribute mages were working together on extending the river, so it could be used continually in phases two and four of the plan.
The ones responsible for blocking the rat's escape path fulfilled their duties by sending down walls of earth, punching the ground with enough force to send down tremors that crashed the tunnels, or using other kinds of magic to make sure the rats don't disperse before or when it's time for phase three.
The mages were worried that the trembling and noises they caused when closing up the tunnels would awaken the rats, but they couldn't afford to waste extra energy on being unnecessarily careful. Instead, they made sure to do it as quickly and as thoroughly as possible. Even if some of the rats woke up, it would be too late for them to escape through the tunnels, and trying the way above ground would get them killed by mages waiting on standby.
As the tunnels in the ground kept collapsing, a ring-shaped indentation took shape around the area where the rats were gathered and sleeping peacefully. The indentation sloped gently since the mages and fighters concentrated their efforts in the center of the circle. The indentation was not unexpected but its size was, as it had both a diameter and a depth of several meters.
While the mages responsible for walling in the rats kept doing just that, trying to go even further down into the ground, everyone else started transporting water buckets in a line, from the river to the circle.
When the buckets filled with water reached the circle, the mages there started pouring it down into the closest intact tunnels, letting it flow downwards.
Just like the rats didn't wake up from the disturbance of the tunnels collapsing, they didn't stir from water being poured on them either, as it just rolled off their protective coats of dusty earth. A few unlucky rats instead got mud coats because they lay in a place where the water gathered, but that wasn't enough to wake them up either.
The explorers kept sending bucket after bucket, filled with water, completely drenching the tunnels.
Although it wasn't enough water to radically lower the water level in the river, it was enough to notice a significant difference, as the dug-out furrow transporting the river past the camp had its edges clearly visible. Before, when the furrow had just been made, it barely contained the water as it was constructed shallowly due to time constraints. But, now, there was a clear gap between the ground and the water level in the furrow.
When enough water seemed to have been used for the tunnels to be sufficiently wet for phase three, it was time for the next step.
Instead of pure water, different kinds of explosives and volatile substances were poured down. Oil, gunpowder, and some magical resources like boom grass. On its own, a single stalk of boom grass isn't dangerous it just lights up like a fuse before turning to ash after burning for a few moments.
But when a mountain of the relatively easily found plant is dried, ground down into a powder, and mixed with water, things change. There is a reason the Merchant Guild controls the sale and distribution of it in low level planes where it can cause serious damage.
It was only thanks to Hugh and the Forest Janitors' connections that they could get enough for their plan. But boom grass, alone wouldn't be enough, so they added more kinds of similar plants and minerals that when put under pressure or come into contact with high heat, react in a volatile way.
The first batch of water was primarily there to make way for the stickier substances and make sure as much of it as possible spreads as far down as possible.
Now, instead of water, the explorers poured down dangerous things continuously into the tunnels, being careful not to use particularly fragrant or smelly items. Even if the rats didn't wake up when they crashed down the tunnels or covered the rats in water, there was no need to push their luck and pour something that smells like food literally down their throats or something that reeks with a stench so vile it might cause them to faint after waking them up.
After everyone emptied the containers with enough stuff to make sure all the gathered rats get exterminated during phase three, everyone except the mages who were participating in the next phase made sure to create distance between themselves and the circle spelling rat doom.
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