A true soldier fights not because he hates what's in front of him, but because he loves what's behind them
Ever since the Changelings were defeated during the wedding of Captain Shining Armour and Princess Mi Amore Cadenza, everypony knew a second invasion would come. It was simply a matter of when.
Four years have since passed and a lot of things have happened.
Twilight Sparkle has ascended into an Alicorn and was now the Princess of Friendship, Tirek escaped, but was sent back to Tartarus, the Cutie Mark Crusaders finally got their cutie marks, and the Unicorn Starlight Glimmer was reformed and became Twilight's student.
Over time the threat of the Changelings coming back became less and less feared by the inhabitants of Equestria, but soon an invasion was all but confirmed.
A changeling spy had been caught and he (after long and not-so-generous interrogations) revealed that Queen Chrysalis had plans to invade Equestria with all her and the hive's might.
Defense lines were set up in preparation, attack plans were set up and just in case, evacuation plans were made as well. Equestria prepared for the worst and when it came, it came hard. The defenses were decimated by a ruthless invading force, unlike anything Equestria had ever seen before. All attempts of repelling the attack were in vain and the Princesses were left with no choice other than to evacuate.
Fighting in this invasion was all but a suicide mission, but still, even civilians signed up to protect their people from the changelings.
Small posts were set up to hold back the invaders until the civilians had been evacuated. One of these posts was Ponyville. It had been fortified and trenches were dug to protect it. 900 ponies were stationed there and so far they had managed to hold up against the attackers who were now stuck in a stalemate, but what the changelings were willing to do to capture the town-turned-fort was something nopony could've expected. Although neither were the changelings prepared for the last stand the ponies of the fort would make.
It was the early morning hours of a late summer day. Changeling troops were standing outside the border with over 30 canisters connected with hoses pointed towards the town and artillery guns locked and loaded.
Silence reigned for a few minutes before the changelings' commander, Void Blade, gave the order to put on their gas masks and fire. The troops acknowledged his order and turned the round handles on the canisters. Green gas soon started coming out of the hoses and it crept towards the town like a mist of creeping death. The changeling began to fire their artillery guns soon after and shells rained down on the town and the trenches as the green gas continued to make its way towards the same target.
Ponyville's troops were asleep and didn't wake up before the first shells rocked the town. By the time the explosions occurred soldiers began making their way out of bed and started getting prepared for battle. Five notable soldiers were former civilians Derpy Hooves, Lyra Heartstrings, Sweetie Drops (nicknamed Bon-Bon), Octavia Melody, and Vinyl Scratch. While their motivation for signing up was a mystery, they didn't disappoint in combat.
As they got their helmets on and loaded their guns multiple ponies began complaining of a weird smell coming from outside, and not long after they had gotten to the battlefield did they realize what was coming their way.
Lyra was the first to identify the gas as being Chlorine gas and since they didn't have any gas mask they began wrapping rags and bandages over their mouths. Although it didn't help much as soldiers began dying left and right from the gas destroying their lungs and skin. Unicorns began casting shield spells in an attempt to protect themselves from the poisonous gas even though it wouldn't do much.
The five friends were inside a shield created from both Vinyl and Lyra, but the gas would still find its way inside and the five ponies began coughing up blood that got caught in the rags over their mouths. One by one they fell onto the ground presumably dead.
The changeling army watched as the gas completely engulfed the town and when it passed they began their approach. All the leaves on the trees and the grass had turned black, fruits lay partially melted around and birds were dropping dead from the sky from the gas poisoning.
Upon reaching a small hill that Ponyville lay just behind they came to a stop as they looked around at the dead bodies of soldiers scattered around the ground.
It looked like they had won and some changelings began to cheer, but their cheering was cut short when a figure began making its way up from behind the hill.
Derpy's eyes slowly opened as she felt an excruciating pain in her chest and she began to force herself up on her hooves again. Her skin was aching and full of melted spots that resembled burn marks, her lungs burned as if they were on fire as she pulled down the rag over her mouth to spit out partially dissolved flesh. She looked around to see other fellow soldiers starting to rise again with the same terrible burns on their faces and bodies. The burns were so severe that they looked like they had risen from the dead. Among those that were still alive were her friends, even though they looked like the living dead there was still life in them. The bloody and injured soldiers picked up their guns as they began to march towards the direction of cheering.
They ascended a small hill and came face to face with the changeling army. One of them had removed his gas mask and was looking at them with an expression of shock and fear.
Derpy coughed a few times before she pulled down the bloody rag she was wearing as she shouted.
"For the Princesses!!!"
Octavia lifted her rifle and shot a changeling straight through the eye as green blood splattered onto the ground. Soon almost everypony was firing at the changelings, who were now running away in panic at this attack of the undead. So much so that they ran right into their own c-wire traps.
Lyra and Bon-Bon were on a roll as they fired shot after shot without missing, Vinyl had been the most affected by the gas but she was still crawling across the ground and firing from her lying position, Octavia was firing with such ferocity she might as well been a different pony whilst Derpy was walking in front bayonet in hoof.
The changelings were in such a state of panic and disarray that they left their artillery guns behind during their retreat. The soldiers took the opportunity and used them to fire on the retreating changelings. The retreating troops could do nothing as their own shells rained down on them and tore them to shreds.
Once the changeling army was out of sight many soldiers collapsed from exhaustion, some of them finally dying from the poison gas whilst some began to cheer.
Octavia sat with Vinyl in her hooves as the latter's time was quickly running out. The two reassured their love for each other with a kiss before Vinyl drew her last breath. Octavia's tears knew no bounds as she cried unendingly.
Lyra and Bon-Bon were limping back towards town when they both fell onto their knees and collapsed into the blood-soaked dirt. Not long after both were no longer of this world, their bodies lying hoof in hoof and muzzles touching in one final kiss.
Derpy looked up at the sky as the sun peeked out from the clouds. The battle was won, but it was a Pyrrhic victory. After one last glance towards where the changelings had retreated she limped back to the town with Octavia following behind, Vinyl's body on her back. The spark of happiness and hope that always lit up the musician’s eyes was now gone. Only a cold and hard stare remained.
The day after the battle, the bodies were retrieved and Ponyville was set ablaze.
Octavia had insisted on burying Vinyl herself. Her body being laid to rest outside the ruins of their old home.
Lyra and Bon-Bon were buried in Canterlot, sharing a single grave.
Because of this battle, the evacuation was successful and the Equestrian people would live on forever remembering the soldiers that saved them at the battle for Ponyville.
