"About time they got here," Burke muttered to herself as the horde made its final approach to the outer layer of fortifications the colony had erected.

"Everything ready?" Wills asked for the fourth time in the last five minutes.

"Yes, everything is ready. You really should have rested when you were told to."

"Couldn't," Wills flicked her antennae, "the scouts were still out there."

"That doesn't mean that you had to be."

"We disagree on that point."

"I know," Burke lifted an antenna and brought it down with a gentle thwack on her siblings head. "Now that the battle has arrived, you're useless. Go back with the other late returning scouts and get an hour of rest. This isn't going to be over by then."

Stubborn, Wills shook her head.

"I'll be fine for a while yet," she said, "I've got a full load of acid and I'm not sleeping till these invaders have felt every drop of it."

"Fair enough then. Just make sure you don't push too far forward. Stick to the plan. Deliver the product and then get to safety."

The two scouts fell into a companionable silence as the horde made its final approach. One hundred metres. That's all that separated the enemy from the first defensive line. After a week of solid fighting, it was a relief to have it come to this.

"About time then," Burke announced.

"Seems like it," Wills agreed.

"Pass the order to open fire," Burke told the general resting behind her.

The ant snapped out a quick salute.

"Of course, Elder. Fire when ready!"

All along the outer wall the order was passed in rapid pheromone communication. Not a single sound was uttered yet a thousand monstrous ants leapt into motion simultaneously. Not far away the human defenders could only marvel and the eerie quiet in which the ants operated.

To the ants however, the 'noise' was deafening.

"Scouts prepare to fire! Long range will engage in ten seconds! Ten seconds! Soldiers and generals will fire in thirty seconds! Wait for the command!"

"Here they come! Are you ready to work?!"

"Five seconds! Five seconds! Check your angles! Don't aim for the front line! Second row!"

"Show them what real monsters are made of!"

"Two! One! FIRE!"

In an instant the entire scouting brigade of the Formica Sapiens, their collective business districts already pointed at the foe, unleashed a barrage of acid skyward.

POW!

A faint whistle emitted from each ant's volley as the acid cut through the air with incredible power. All together the shrill sound pierced the air but faded quickly as the acid lost momentum and began to reach its apex. From there, it fell.

Even from this range, Burke could see the rage and pain on the monsters’ faces as the acid fell amongst them, eating into their bodies and chewing into their flesh. Any monster who fell was set upon by its fellow horde members in an instant, torn apart and consumed in seconds. Hundreds of monsters were felled in this way but barely made a dent in a sea of enemies that lay before them. The ants were undaunted.

POW! POW! POW!

The scouts continued their steady barrage, firing in sequence as a well drilled unit would.

"I'm about half empty" Burke observed, "what do you think of the range?"

"I think it's close. I haven't been tracking the time," Wills replied.

"Soldiers and generals, FIRE!" the order rippled down the line.

POW! POW! POW! POW!

The rest of soldier caste on the wall joined in the barrage. So much acid filled the sky it began to fall on the horde like burning rain. The ants were careful to spread their fire as much as possible. It wasn't as if it were possible to miss in this scenario, but to inflict maximum damage on the horde the ants didn't need to inflict fatal damage. It was better to wound as many as possible and allow their ravenous allies to deal with the rest.

Despite the acid that poured from the sky and the creatures who threw themselves on their wounded brethren, the horde continued to advance, an unstoppable wave of momentum that couldn't be halted. Despite the damage caused by the acid bombardment, the colony may as well have been spitting in the wind.

"I'm empty," Burke declared, reorienting herself so she could look out over the wall once again. "Ten more seconds till they hit the wall I think."

A pervasive feeling of determined calm possessed the warriors of the colony. Everything was on the line today. Mistakes could not be afforded, not even the slightest mishap. Unless every member fought to their utmost potential, the colony would fall and that could not be allowed.

The ants had planned a defence in depth to maximise their terrain advantage and the unthinking nature of their enemies. The battle would be long and brutal. There would be an opportunity for the desperate rage of the final stand, but not yet.

"Alright then," Wills replied, retreating from the wall where her position was taken by an eager soldier. "I'll head back and rest."

"Good on you," Burke approved, "I'll try and make sure some of them are alive for you when you come back."

Wills waved an amused antennae and made a hasty retreat. If she wasn't going to be fighting then she had no business on the front lines, muddying up the waters.

With her sibling gone, Burke focused her attention back on the horde as it crashed into the first earthen rampart the colony had erected. Monsters of dozens of shapes and sizes crushed against the solid barrier and were smashed into the ground as those behind them climbed over them. Roars and screams of rage and the dying rattle of monsters filled the air as the soldiers in the front row began to lean forward and chomp at the first enemies to come into range.

Burke took her position, not at the front but one row behind. The council had determined this was as close as any member was allowed to get to the thick of the fighting. Truth be told, only the soldiers and scout portion of the twenty would dare fight here. Burke felt it was necessary that the council shoulder the risks of the colony along with their siblings. They weren't some protected caste whom the colony existed to serve. The very idea was repellent. They existed to serve the colony!

The soldiers at the edge of the wall continued to lunge forward, snapping at monsters below Burke's line of sight. There was no risk the soldiers would fall, they could grip as well as any other ant, obviously, but if they were caught hold of they might be pulled down.

The horrific din of the horde reached a fever pitch as the monsters pressed against the wall and sought to climb it. The wall wasn't immense, only three metres tall, but most monsters weren't as adept at climbing vertical surfaces as the ants were.

But some of them could and after a few more seconds Burke began to see the first creatures reach the top of the wall. Like lightning, Burke lunged forward and brought her mandibles closed on a spider that had poked its hideous, fanged head over the edge of the wall.

The beast’s eight legs (disgusting!) scrabbled and scratched at Burke's carapace as the scout leader pulled the creature back over the wall. In seconds it was surrounded by soldiers and scouts. The ants worked together and ripped the monster apart before it could free itself. As the soldiers pulled back to return to their positions, healers rushed forward to grab the Biomass. They'd use it to create stockpiles close to the front to assist with their healing efforts.

First one down, Burke told herself. A heck of a lot to go.