Turns out that acid that can propagate itself almost infinitely can pile up if you give it enough time. After I chose and began to use the multiplicative acid mutation, more than a few of the scouts took a solid look at it and liked what they saw. If I were to try and produce twenty mega-litres on my own it would take far too long. The acid is able to replicate itself, sure, but with only one mutation dedicated to the effect, it isn't that powerful yet. A hundred ants working together was required to build up this tidal wave of delight.

The moment the flood begins I can no longer see the reaction of the Legion forces which only a moment ago had dominated the approach to the gate. The downward sloping tunnel works perfectly to direct the absurd rush of acid as if foams and froths before my eyes and pours toward the approaching army. The sound is horrendous as the acid crashes into the hard stone of the tunnel and reaches out from there, hungry for flesh and metal. It might be unfortunate for them, but the Legion provides both.

There isn't much I can do to further enhance the damage of this particular strike, so I prepare for the next stage as we wait to see how effective this tactic is. My inner minds focus as I bring forth the power of the gravitation mana, crunching it down and compressing it in on itself again and again as I mould a tiny ball of screaming death within myself. Even though I shouldn't be distracted whilst attempting to do this, I can't help but extend my main mind forward to get some sense of what is happening.

What I detect immediately is the titanic battle taking place between the Legion mages and the spell weavers of the Colony. Hundreds of minds warring against each other as they attempt to seize control of the ground around them. The flow of mana is hectic in my eyes, swirls, gusts and ripples have been replaced by tears, whirlpools and hurricanes as each side tries to wrench the flow into their control. The Legion has drawn on their mastery of earth to modify the shape of the tunnel, blunting the force of the river of acid and diverting it to the sides, though my siblings have resisted their efforts at every turn. In enacting these changes however, the mages of the enemy have been forced to abandon their efforts to stymie the ants attempting to collapse the roof down on their heads. Even as the torrent of acid slides down the side of their barriers, eating into their shields of light as it continues to propagate itself, the battle of minds surges overhead.

If the humans falter even for a moment, they'll be in for a nasty surprise. There are metal spikes that weigh tons each lodged into the stone up there. If they are allowed to fall it's going to be a bad day for whoever gets hit.

This is the strategy of the Colony when it comes to this defence. One attack isn't going to be enough to divert the power of these soldiers, they're too strong, too experienced and more than we can deal with at our current level of strength. Since one strike won't defeat them, we'll hit them a hundred times. A hundred times a hundred. However many it takes until they fall. So we strike from multiple directions at once, the acid tanks, the mages in the stone and more.

Never the kind of creatures to let something go to waste, I know that the acid is going to be collected in special holding tanks carved out of the stone deep below the tunnel. The Legion may never have noticed the holes in the stone beneath their feet when they began their ascent towards the gate, but they are certainly there. A hundred metres below the tanks await, from which the acid can be pumped back to the top of the tunnel. An ingenious system that hundreds of carvers spent a week carving out. Sadly, it'll take hours to refill so we can only deploy the acid again if we manage to repel this first approach from our enemies.

"How did it go, Eldest?"

It's Ellie, hiding in a chamber on the other side of the wall to my right.

"I think we got their feet wet at the least, but it hasn't stopped them. On the plus side, they aren't coming any closer right now."

It took over a minute for the tanks to fully empty themselves, dumping out acid at a shocking pace. As the deafening roar fades away I can finally hear myself think and more than one ant clicks their mandibles in shock at the ferocious display.

"In other words, they're right in position?"

"Yep. Think you're pets are going to be up to the task?"

"They'll make you proud, Eldest."

"Let's see it."

[Is it possible that I can join them, Master?] Crinis asks me.

[No, Crinis. We've gone over this. I need you here with me. Let's watch and see how they do.]

The blob attached to my carapace wiggles in a mix of frustration and happiness as I turn my attention back to the ever hungering ball of mana spiralling in power within my mind. The bomb is reaching the critical point of overload and I need to devote all of my attention to it but I can't help but keep my eyes peeled for the attack of the core shapers.

The moment the Legion becomes visible again behind the haze of acid mist in the air it's clear to see how they were able to survive. Deep gouges have been carved into the ground on either side of their formation. From the ruined appearance of the tunnel floor, it looks as if a combination of magic and sheer physical strength was used to create these gashes, which means they must have directed weapon strikes at the stone to help break it up. More than that, their soldiers have tightly packed together in a narrow column, shields pressed against each other with their defensive abilities activated. From my position near the gate they present a layered wall of golden light which patches of acid still cling too, sizzling away.

It might be a pain, but I can't help but be impressed that they survived. Sorry Morrelia, but that's not the only trick we have up our sleeves.

It only takes seconds for the order to slip down the chain and I see something that most people would rather not see in their lifetimes. The furious acid has burned away the thin coating that once covered the floor to reveal a narrow gap in the tunnel walls, close to the floor. If I weren't looking for it, there's almost no chance I could see it at all, it's so narrow. From that narrow gap on both sides a darkness wells up and then begins to pour out onto the floor. All the way up and down on both sides of the Legion column a tide of pure black is massing. From out of the shadows, slowly at first but quickly gathering speed, extends a forest of tentacles, hundreds, thousands of them, as the darkness moulds itself to reveal its true form.

Centipedes.