June 3, 1942
It had been one day since Equestria appeared in the Pacific Ocean, one day since war was declared. The ponies deemed humanity unfit for existence; they couldn't have picked a worse time. The ponies must have been expecting the current war to leave humanity vulnerable, they were wrong. The Imperial Japanese Navy and the U.S. Navy had agreed to a parley mere hours after the Equestrian's announcement of "conversion" and while the arguments were heated, they came to a temporary alliance. Both factions didn't believe the war would be long, so they agreed to go back to killing each other the day after it ended.
Fleet Admirals Nimitz and Yamamoto along with Admirals Fletcher, Spruance, Kondō, Nagumo, and a few other Japanese and American Officers were currently running over logistical statistics and battle tactics. The former enemies would still give each other hostile glances but were willing to put aside their mutual hatred to come up with a battle strategy, that will insure the destruction of Equestria with minimal allied causalities and swift operational success. The plans were being set, the dominos falling into place, soon Equestria's trial by fire would come, and the fate of humanity decided.
A lone PBY Catalina flew lazily overhead of the island known as Equestria. The co-pilot looking down at the island through his binoculars. He could see a mass of ships around the island, and laughed. They were wooden hulled coal fired steam frigates, he was fairly certain his Catalina could take the majority out. "So how are things in pony land?"
The question came from the pilot, he replied simply enough. "They have toy ships an' candy canes, we should be very afraid indeed." They both chuckled.
Taking advantage of the high altitude cloud cover the PBY made its way back to the fleet, having already radioed ahead their observations.
The decks of American and Japanese aircraft carriers were abuzz with activity, the roar of radial engines filling the air as one by one planes took off of the ships. Devastators slowly clawed their way into the skies, followed by the more nimble SBD dive bombers, along with their Japanese counterparts; the B5N Kate and the D3A Val dive bombers.
After a little over an hour's worth of flying the Equestrian fleet came into view, bomber pilots began their attack runs. Multi-coloured beams of energy began to ascend to greet the oncoming threat...only to dissipate harmlessly upon impact.
"Aw isn't that cute? They're shooting little rainbow lights at us." An American pilot spoke into his radio in a voice similar to Micky Mouse, eliciting chuckles from the other Americans.
Pegasi flew up to engage the now vertical dive bombers, only to be shredded by their offensive armaments. The few who made it through the hailstorm of bullets fired their crossbows to little effect. The planes quickly sped past them, their dive brakes extended and targets locked.
The American SBD's dropped their payloads and pulled out of their dive, 500 pounds of death impacting the slow and vulnerable Equestrian ships. Then a sudden shout came across the radio on broadband. "Kamikaze!" And with it the Japanese planes flew directly into their targets, destroying themselves and their enemies.
An American pilot whistled before he spoke. "I knew them Japs were crazy, but this? It's only 1942, they're not suppose to do that until things start going badly for them, damn bastards didn't pay attention to their history class."
This got a few laughs out of the Americans, who flew by the Devastators and Kate's heading for the Equestrian mainland.
Again more energy bolts tried to bring down the planes, but again they just fizzled out upon impact. A pilot just shook his head before speaking. "These ponies don't seem to understand magic doesn't work well here, poor things, it's gonna make killing them that much easier. Tsk, tsk, tsk."
"Quite frankly, I'm surprised it works at all." Another pilot said pointing a thumb at the rainbow lightshow surrounding the planes.
"Well the island itself is still filled with energy from the rift they came through, in the surrounding area magic is still possible, although being we aren't from magical la-la land we are immune." Yet another pilot replied, only to be shot down by the plane behind him.
"Poindexter." The pilot stated and the rest of the squadron laughed.
It's a bombrun day, it's the Naval way! A bloodred sun is on the rise. The men sang as they began their attack runs.
The bombs started pouring out of the American and Japanese bombers as they flew over the mountain side city and some costal cities. Before they too turned back towards their carriers, burning cities in their wake; oh and the Japanese didn't Kamikaze this time.
With naval artillery clearing the way American Marines established a beachhead with only a dozen causalities. Those causalities being the idiots who like to look down the barrel of their loaded rifles every five minutes, yes they got what was coming to them. Fools, don't look down the barrel of a loaded rifle!
A General and other officers and men were gathered around a table with a crude map of Equestria drawn on it. "Okay, I want the 32nd infantry to flank west of this town here" the General said pointing to a small town on the map, "at the same time the 12th and 15th infantry will head east in a long arch and cut-off the enemy's retreat. The 1st and 2nd armoured divisions will roll up straight through the town and flush out anything still hiding."
While the General spoke a Corporal whose name tag stated him as L. Jenkins fiddled with an C-ration that listed it supposedly contained "chicken". The General continued to order men to different locations and when Jenkins finally tuned himself in he heard the word "go", so naturally, he went.
"Alright chums, lets do this! LEEROY JENKINS!!" the Corporal shouted as he charged straight down the middle into enemy lines.
"Did he just..." Was all the General could say.
"He just ran into enemy lines!" Another officer replied.
"Goddammit Jenkins! Get your ass back here!" The General shouted but Jenkins was already shooting away merrily at anything bright and colourful.
"Well, it looks like we have to go save his ass." Another soldier stated to which the others nodded and rushed after Jenkins.
"Goddammit! Follow your damn orders!" The General fumed before giving up and pulling out his sidearm, joining the rush, along with the Shermans of the armoured divisions.
Jenkins was far ahead of the others, the pony Royal Guard put up shields and readied lances, while he shot and charged. The rounds from the M1 Garand ignored the shields and impacted the Unicorn Guards behind, killing them in a bloody heap. Soon more rifle fire and submachine gun fire joined in the killing of the ponies. Bits of bone becoming projectiles and slamming into the others of the close formational Guards. The Shermans crested the hill and let their 75's open up with High Explosive ammunition. The rounds detonated in the centre of the group; limbs were blown off of the stallions and shrapnel shredded their comrades. The stallion closest to Jenkins took a 30-06 round to the skull, blowing the back out and sending bits of skull and brain matter into the pony ranks. A bit of skull buried itself into the eye of another Guard, which collapsed onto the ground screaming while fluid and blood drained out of his punctured eye.
The Royal Guard forces in Ponyville were quickly overrun by the soldiers and machines of the United States. Any forces still resisting were being slaughtered and the town was being levelled by both weapons fire and the tanks driving through the poorly constructed buildings.
They advanced through town after town, city after city, leaving a trail of destruction in their path, all following the infamous Leeroy Jenkins.
"Celestia... I-I think w-we made a mistake b-by tr-trying to convert the humans." Princess Twilight whimpered to her mentor, fear evident in her voice. She and her friends had dawned their Elements as a last ditch attack to stop the human army, although Twilight and Celestia both knew it wouldn't work. It was mainly to keep hope in her subjects eyes, that they may see this through. Canterlot was full, beyond full, after the initial air attacks the Royal Guard were ordered to evacuate the civilians from the outlying towns and cities.
"I believe you are right Twilight, I have made a grave mistake and it may have cost me everything I hold dear. Even you Twilight. I'm sorry." Celestia's voice was full of regret and sorrow, she had made mistakes in her past, but none could rival this one. She looked at all the fear filled eyes of her subjects and a single tear escaped her eye.
There were two loud cracks and the Guards by the entrance collapsed, dead. Then it was heard, the sound that could strike fear in ponies for miles around. The sound of death.
"LEEROY JENKINS!" Jenkins shouted after killing the two Guards and rushing into the throne room of the ponies and witnessing the leaders of their enemy cower in fear. He smiled and took aim. Suddenly when he went to fire the six mares started glowing and hovering, Jenkins took his finger off the trigger to watch in amusement as they attempted to defeat him with magic. The rainbow of light hit him, completely engulfing him from outside view, and ponies cheered, that was until the energy dissipated and he stood there with a cocky grin and his C-rations. "At least I have chicken."
Another Alicorn, this one white with a red mane appeared in a flash of light, leaving Luna and Celestia wide-eyed. "M-mother? Is that you?" Luna asked with hope filled eyes.
A man then stuck his head out from behind the Alicorn. "Nope! Chuck Testa!" Before he and the Alicorn disappeared in another flash.
As this occurred the rest of the army came in and open fired on the Equestrian rulers and the Element bearers, although the civilians were spared the wrath of the soldiers. They kept their weapons trained on them watching for any sudden movements, the ponies pushed back as the weapons were aimed at them. Then the General walked through the entrance, General George S. Patton, wearing a look that could kill from miles away.
With Equestria's rulers dead and no way for the ponies to return back to their own dimension they surrendered.
The Japanese and Americans went back to their war the next day; June 4th 1942. The battle of Midway proved a decisive victory for the Americans and the tide of the war was changed. The rest, you can say, is history.