Side note, I'm going to be using a mix of the mainline games with inspiration insect Armageddon and Iron rain.

In 2010 a signal was received from outer space indicating the presence of intelligent life. This caused a flood of activity across the world. Later that year most of the major nations of the world signed the Defence act. This act soon leads to the creation of the multinational organisation known as the Earth Defence Force, or EDF.

On 2nd of March 2017 Alien ships arrived over several major cities on earth. But their response, wasn't peaceful. With the use of giant bugs and machines, the Aggressors attacked and the EDF was deployed.

Despite massive casualties, in 2019 the aggressors were forced off the planet. The EDF won, but people knew that they would be back. Using alien tech, the EDF became to most technologically advanced military on earth. This lead calls for the EDF to be disbanded, but the Defence act prevented this.

After bitter arguments several nations left the Defence act, but the members of those respective nations in the EDF refused to leave. This led to the Defence war, a short war in which the nations who left lost and were forced back into the fold. After the war, all nations were then forced to relinquish their armies to the EDF with only a defence military allowed.

In 2028 the Aggressors attacked once again. This time the EDF couldn't hold for long and was forced to fall back to major cities. This led to a 7-year defensive war which ended in 2035 with the destruction of the giga-creature Raznid and EDF victory.

2045 the Gate appears.

OOOOO

Ginza was busier than normal as two main events were taking place. The first was a manga festival, but the second was an open concert done by the Jet Angels. The Jet angels were a 7-woman idol pop group with each member coming from different nations. Each one wore a jet gear, a jetpack that allowed them to fly though the air like their name suggests. Unlike other idol groups however, these girls were combat experienced soldiers of the EDF.

Ever since the aggressors were destroyed several years ago and the world began to rebuild, the EDF were considered to be heroes. While people liked this, others wanted to do more. Thus, the Jet Angels were born, part propaganda tool, part moral booster, they played for soldiers to raise spirits. Each member was from one of the major EDF nations with their outfits mirroring their nation of origin flag.

But the idol group wasn't of interest to Yoji Itami. The otaku was more interested in the manga festival as he made his way to the location. But he was so caught up with what he was going to buy, he hit a pillar. People began to crowd him as the man moaned while the red mark on his face pulsed.

"Owww," he moaned.

Little did he know what this was only the beginning of something that would change the world.

OOOOO

In the middle of Ginza something began to form. A multi-coloured shimmer of light began to take shape getting peoples attention. Soon it began to take shape and form into a roman like structure. White marble with a black entrance that had no back to it. Looking on people around began to take out their phones and take pictures of the strange structure. But as they did this, glowing red dots began to appear from the blackness of the building. Moments later pigmen, orcs and more emerged from the building charging in killing all in their sight. People ran and screamed in panic.

Not long after the demi-humans emerged soldiers dressed in roman like armour emerged. More disciplined than the demi-humans they marched out in disciplined ranks with the cavalry lead by General Errus Kai, the leader of the army. As he emerged, he was blinded by the heat and the sun. His eyes soon adjusted as did his fellow commanders. Their sight then soon fell on the buildings that dwarfed them. His mind spun as he gazed upon the buildings of glass and steel in awe.

"Amazing," one of his fellow generals said as he looked up as well. "They must have some form of master builders to make these marvels,"

"We will make them our own for the Empire," said another.

"Indeed, we will," Errus said before he drew his sword. "Charge!" he yelled and the imperial army marched into this new land capturing and slaughtering all in their way.

As they ventured into this new land, they soon began to surround a black and white caste of strange architecture. But it was to be expected given what they had seen in this strange world. The enemy had barricaded the walls to the castle so two orcs moved up to try and smash the main gate down. But before they could reach it a lone man laned in front of them. He was short with dark skin and a wide brim hat which was tilted slightly to one side.

In his hands were a pair of curved blades. Small, but they looked deadly. He also wore a green uniform with some form of strange armour that looked like little more than blocks on his limbs. There was some sniggering with the soldiers as the one lone soldier just stood there ready to attack. The orcs smiled and brought their hammers up ready to take this small soldier down.

"Ayo Gorkhali!" the soldier then yelled before jumping higher then seemed possible.

Suddenly he then sped forward and beheaded the tall orc before turning to the next one. This one managed to try and hit the soldier but again he moved with almost superhuman speed out of the way towards the orc. He then stabbed his knife into the belly of the orc before jumping bisecting the orc killing it as its organs fell out. The soldier then landed in front of the gate.

"You shall no pass," he said but the language was strange to the general, consequently he didn't understand what the man said.

But the actions of the man made the General pause. How could such a small man take down orcs three or four times his size? Just then more soldiers joined him, not as small as the first man but each one wore a similar uniform and armour. They were also equipped with a large slab like shied that look to heavy for them to carry. The weapons too also looked too heavy too normally carry.

His eyes narrowed at the warriors in front of him. "Advance!" he yelled and the demi-humans were the first to walk up.

But they didn't get far. Several of the enemy warriors had gigantic hammers they when brought down it let out some form of shockwave then sent the demi humans flying. The enemy then advanced with their shields up. Despite the superior numbers of the demi-humans the enemy advanced, pushing them back before binging their weapons down and sending more demi humans flying or crushing them. The force the general began to back up in fear as the enemy advanced more and more.

Before they could do anything, else loud noises made the Imperial soldiers look up. Several lying machines moved across the sky taking out the wyvern knights with little difficulty. More nose, this one sounded like roars of animals. He turned to look down to see blue metal animals of some kind move up close to them. Before he could do anything, sounds of thunder and fire echoed from them taking out the demi-humans and his soldiers. It was then he knew, they picked the wrong enemy to fight.

OOOOO

News of the attack in Ginza spread far and wide making people panic and worried if this was another aggressor attack. But those fears were quickly used by the UNEDF secretary general. A news conference was quickly set up in Japan by the General. Takuma Yagami walked out onto the stage and onto the podium. As he did flashes of camera's sounded making him bink slightly before he spoke.

"The battle in Ginza was a tragedy that no one could have predicted. However, it is clear that this attack was not done by the aggressors," he said with a clear air of authority. "We have not detected any kind of energy gem or aggressor signals with the enemy forces. We are dealing with an attack from an unidentified hostile nation," someone then spoke up.

"General," someone spoke with a thick American accent. "What does this mean for the EDF?"

"There has been some debate about how to deal with this," Takuma admitted. "The EDF is meant to protect the lives of humanity, not destroy it. However, given that this army is not terrestrial in origin it has been agreed that a small force will venture into the Gate and find those responsible and make them pay for the damage they have done. This has been backed by 75% of the UN council,"

"Have you thought about destroying the gate?" another reporter asked.

"We have indeed, but we have decided against it," Takuma said. "If we destroy this gate there is no guarantee that we will remain protected from another attack, for all we know another gate could appear in America or Europe or someplace where the enemy can fortify. The risks of destroying the gate are too high,"

As more questions were asked Lieutenant Yoji Itami sighed and turned off the tv moaning as he fell onto the bed looking up at the ceiling.

"Why did they have to close the convention early?" he moaned.

OOOOO

The EDF canteen was full of soldiers. The news that they were going into the newly dubbed Special Region had filtered down to them. So, they were preparing as best they can. The newly promoted 2nd Lieutenant Itami sat just playing with his food depressed at the cancelation of the exhibit. Something he wasn't happy about even with the promotion.

He didn't care about being a hero, all he cared was saving people and his hobby. But despite what he did the event close before he had a chance to get there. The depression set in as he just looked at his food and a Sargent walked up to him.

"Hey your Yoji Itami, aren't you?" he asked. "The Hero of Ginza. I'm Takeo, I'm just transferred her from Nagoya base. Man, it's such an honour meeting the you for the first time. What's it like being the hero? I bet women faun over you,"

That hit a nerve. "Shut up," Itami moaned. "I'm annoyed. The sale and exhibition ended up getting cancelled, and after it happens, I don't even get weekends off,"

"You were given a commission by the Councillor, and even got promotion. Kama is going to kick your ass for complaining," Takeo shot back.

"It's not like I wanted to get promoted," the LT muttered.

"Jezz you have no ambition at all, do you?"

"Look I work to support my hobby. So, if you had me choosing between my job and hobby, I'd give my hobby priority, without question,"

Takeo frowned at his commanding officer before smiling. "Hey by the way Itami, I've kept it a secret until now. But I was at the sale and the exhibit that day,"

Itami just recoiled in jealously as he looked at the Sargent. "You were?" he practically yelled.

"I wasn't able to do anything," Takeo admitted. "I couldn't bring myself to say…" but the LT didn't like that.

"So, what about the loot? What did you get?" he then grabbed Takeo. "Wanna come to my place tonight?"

This wasn't a conversation; this was an interrogation.

OOOOO 3 months later.

8000 soldiers along with tanks, troop carriers, and more stood at the closed off section to the Gate. Each one ready to move out at a moment's notice. The UN had prepared this for the past few months, now they were ready. 4000 troops from the EDF Asian divisions, mostly from Japan and the rest were either from Europe or America with a few from Australia, Africa and South America. This force was known as the 'Special Region Task Force'. The vanguard into the special region.

As they waited to move, General Hazuma stood before them. The veteran of the Aggressor war stood tall and proud among the others.

"I'm General Hazuma!" he yelled. "Your commander for this mission! Many scouts have entered though the past in the past month, but nobody knows what will happen to us in the special region. Thus, you must be ready for combat as soon as we cross the Gate,"

As he spoke, Itami noticed a girl and mother standing in front of a row of flowers. It was clear that they were grieving. He bowed his head slightly in response.

"We will be going though momentarily!" Hazuma yelled.

At that everyone loaded their weapons and climbed into their vehicles, as they did tank engines roared into life.

"We will show the enemy what they have brought upon themselves. We faced down the Aggressors, we destroyed Raznid!" he declared. "We'll show them what the Earth Defence Force is made of! EDF!"

"EDF," the soldiers yelled. "EDF, EDF!"

"Roll out!" Hazuma yelled.

EDF Special Region equipment:

EDF uniform:

It looks like the uniform from Starship troopers, but olive green with the armour having pouches on the chest and the PA gear from Iron rain.

PA gear:

PA gear, or personal armour is an exoframe that is designed to enhance the soldiers speed, strength and stamina. Highly modular, the frame is standard issue for all EDF soldiers regardless of rank and position.

Trooper:

The basic of the EDF, the trooper is a highly trained soldier of the EDF.

Heavy trooper:

Unlike the normal trooper, the heavy trooper is as the name describes. Their PA gear is equipped with heavy armour slabs that double as jets to support the frame when landing or boosting. A notable difference is that the power pack of the frame can allow for dual wield weapons as well as shoulder mounted weapons. Outside of vehicles, heavy troopers are the only ones who can use weapons such as cannons.

Jet Trooper:

The lightest of the classes, the jet trooper is equipped with a jetpack and stabilizers that allow the trooper to fly with ease. However due to this they cannot weald heavy weapons. Instead they tend to use energy weapons or sub machine guns.

Type 2040 Anteater AR:

The standard weapon of the EDF, the anteater was made in response to the aggressor threat. A high calibre weapon with a high rate of fire, the Anteater is the workhouse and favourite of the EDF. It looks like the starship troopers morita rifle from the movie but not as long. Something similar to what Razack has.

Type 2039 Gorilla MBT:

Modelled after the Abrams tank, the Gorilla is the primary battle tank of the EDF forces. Despite having only, a 4-man crew, one 110mm gun and a top speed of 40kph the Gorilla has proven itself to be a reliable tank.

Mark 4 Kuratas:

Based off the Kuratas design from 2012, the mech was designed as a squad support weapon. But due to the effectiveness of it against the Aggressors, divisions of mechs were created. The Mark 4 is the result of years of trial and error. Standing 5.5 meters high, the MK 4 is a highly modular weapons platform with hard points on its shoulders for weapon placements. As standard, the MK4 has an armblade on both arms and a twin 5.56 short barrelled chain gun on its right arm. It also carries a 60mm autocannon, but this can be swapped out with a chaingun or other heavy weapons.

It's legs also support tacks which allowed he mech to move even if its legs are damaged. This also allows it to keep up with other forces.

Type 3 Megalodon Rail tank:

Twice the size of the Gorilla, the Megalodon is equipped with a Railgun that can punch though anything. Slow and hard to manufacture, the Megalodon is mostly used as an artillery unit and not as a proper tank.

Type 37 Raven:

Based off the Bradley IFV, the Raven is a multipurpose platform. It's turret can either be equipped for an anti-air role or transport role.