That when watching Gate I thought of a what if scenario that the Empire decides to invade a Earth but in a Sci-fi setting with you know lasers and spaceships. So I thought with making a crossover with series like Star Trek, Star Wars, Halo, and more such as trying CoD Infinite Warfare but when writing the few first paragraphs thought it was bad and gave up so I thought making my own idea to how it would be but didn't because I thought people wouldn't like it so I just let it be. Then I read Thus the UNDF Fought There by Modern Military Power and was determined to write it. So here I am. This is my first story so quality may be not the best but I'll do my best

Prologue: Part 1

2018: On December 23rd, NASA and other space agencies around the world detected unknown objects coming towards our planet at speeds faster than light. Soon on every device all broadcast was played to which answered our long lasting question of whether we are alone. They were called the Exilan, as they weren't here in peace as their reason for coming was for the enslavement of mankind and conquest of our home in the great honor of their empire. Soon all the world's militaries was put at high alert as nuclear missiles were readied to shoot down their vessels, as ground troops were mobilized and sent to major cities, the world's air forces scrambled at the ready, navies at the ready.

At noon they touched down, the first volley of nukes didn't do much but the second volley of 50-100 megaton warheads which were classified warheads from the US and Russia that it destroyed several of their ships which they retaliated with kinetic strikes on major cities killing 46 million people immediately The air battle was costly as the world's modern jet fighters couldn't match that of those across the stars. On the ground, armored vehicles such as tanks were getting vaporized by vehicles straight out of war of the worlds as Earth's ground forces needed their best tanks to have a 4:1 advantage against them.

Two hours in to the Battle something unexpected happened. That coming out of our oceans and breaking out of the ground were alien ships miles long as they began attacking our invaders. Their ships destroyed the Exilan vessels with laser weaponry that only needed one shot. The newcomers airceft were decimating the Exilan fighter air craft with ease as they helped destroy the nicknamed "tripods".

Soon enough everything Exilan was destroyed by these newcomers. Soon Earth's remaining aircraft were tasked with finding more about these alien that had saved us. That when going the alien aircraft that areas that looked like a cockpit, had no one piloting them, soon a helicopter was sent to one of the aliens vessels as it entered a supposed hangar bay. They were soon greeted by an A.I. that told of their origins and purpose.

They were called the Precon a hyper advanced civilization that was the dominant in their galaxy as they were capable of traveling millions of times greater than the speed of light, and weaponry that was millions of years more advanced than Humanities invaders. The reason the AI was the only ones left was that when visiting another galaxy that they encountered what they called the Conquerors who were a savage race that had conquered two previous galaxies as the Precon's was next. That Precon was more advanced but were pacifists while the Conquerors had the numbers and cunning in war. That it was clear that the Conquerors would win to which they knew what they had to do. That the Precon created ships with self reliant AIs that had the most advanced technologies the Precon ever created were sent off to any worlds harboring life as if the Precon couldn't defeat them then whatever species that the ships find could while they fought for their homeworld with their last breath.

That with this Humanity had their best minds work on these vessels which had facilities that would give Humanity a head start as they were being taught by the AIs on the develop the technologies needed tl protect themselves and fast as it was discovered that that the Exilan will be back in a hundred years and seeing that earth had ¼ of its military destroyed, 1/6 of the world's infrastructure gone, and the deaths of 58 million people in three hours made Hummanity rapidly develop itself.

2021: The worlds first energy based weapons are being produced as well as the improvement in projectile based weaponry in the form of railguns as navy ships are quickly retrofitted as tanks having their guns replaced, handheld versions being mass produced and issued for troops.

2023:The procurement of nanotechnology has helped Humanity in the medical field as the cure for cancer has finally come as well as for other diseases that were once untreatable as now the average human life span has an estimated increase of 140 years.

2025: FX-40 Meteor is shown to the public as the world's first space fighter as it bore some resemblance to the F-35 but 30% larger and is twin engine. Specifications give it a top speed of 80,000mph with it capable of making two round trips to the moon, a VTOL based aircraft, with it being 25x as stealthy as the F-35 by using materials fabricated by the Precons. Armament is two plasma canons that fires at 1200rpm, eight AIM-18 heat seekers capable of being operable in space, four AIM-125 long range radar based missiles, and could carry two large bombs designated the GBU-41, as it also has attachable hardpoints for a larger weapon load out. Defensive system is Humanity's first shield which can hold up to 18 kilotons of force and improved flares and chaff.

2027: Build in the internal shipyard of a Precon vessel the first human space warship the Corvette Yuri Gargarin. Measuring at 400 meters the ship's sublight speed is 60,000 mph with an FTL speed thanks to a Precon Warp drive that is 100,000 times the speed of light which is to be classed as Warp 1. Crew compliment is 80 officers and 230 enlisted with a marine compliment of 400. Ship's main weapons includes a large railgun the ships is built around that fires a 500 ton depleted uranium slug at 2% the speed of light, an omnidirectional laser cannon similar to that of the ones used by the Precon as it was capable of destroying an asteroid 100 miles in diameter at 20% power, and four 50-megaton warheads, and two newly developed 10 gigaton warheads. Secondary weapons are 8x twin railgun turrets firing a 12in. tungsten round at 0.2% the speed of light, 10x twin laser turrets that produce 200 megatons of energy, and newly developed Viking II anti ship missiles that travel at Mach 20, with a blast yield of 100 tons of tnt located in 10 pods holding 20 missiles. Defenses is an energy shield that withstand 160 gigatons of energy, 10 feet of titanium A hull armor, and fifty twin 40mm bofors gun. Air wing includes twelve FX-40 and four refitted V-22.

Later in the year the formation of the United Nations of Earth is formed as nations given their independence for a more Unified government.

2030: Human population reaches 15 billion with the enactment of a child policy that states a family must have two or more children, with a longer living population, as the a poor regions of Earth began to see development to were terms of living is beginning to match that of supposed 1st world nations. The Moon and Mars is being colonized as small towns of 100 people are developing quickly. Small outposts on the outer Solar System are being set up as an early warning system against alien threats.

2032: Rockstock Corporation is formed which is a private developer of new technologies from that of the Precons as they are also a private military force to aid the UNSF in certain areas as they work in medicine, robotics, military hardware, and start up new colonies. Rockstock funded city on Mars reaches a population of 10,000 as they also sent colony ships to Alpha Centauri and Proxima Centauri.

2033: First Batch of the T-280 Valiant Dropship is produced. The T-280 is a transport aircraft capable of flying in space as it was a continuation of the V-280 Valor Program as it had his rotors replaced with that ion engines for a greater speed of 40,000mph. Troop capacity is 16 men as it is armed with a plasma based minigun under the nose, and varying weapon types for the side doors.

2035: The first Human made Artificial Intelligence is created with the knowledge and advice given by the Precon AIs. That they are implemented on board warships, aircraft, squadrons, and entire regiments, as well roles in government and civilian sector. That as the AI had human morals and feelings that the UNE declares AI rights the same as human rights for coexistence as some thought of having the dead live on as AI.

Two months after Earths first Orbital shipyard is completed as it is to increase Humanity's industrial capacity in shipbuilding to ease up the shipyards on Earth, and the ones located within a Precon vessel.

2036: The second class of space warship is completed with the introduction of the Philadelphia Class Frigates is created. At 676 meters in length with sublights at 57,000 mph with FTL being 105,000 times the speed of light being measured at Warp 1.05. Crew compliments is 97 officers, 289 enlisted, and a marine contingent of 590. Main weapon is a railgun firing a similar round to the Gargarin Class but fires at 2.3% the speed of light and the omnidirectional laser canon, six 50-megaton warheads, and three 10 gigaton warheads. Secondary weapons are 11x twin railgun turrets firing 12in. rounds at 0.3% the speed of light, 14x twin laser turrets that produce 230 megatons of force, and 13×20 Viking II missiles. Defensive Systems is an energy shield that could hold to 200 gigatons, twenty feet of titanium A, and fifty-eight 40mm bofors. Air wing is twenty FX-40 and seven T-280.

2038: Humanity uses new defense satellite systems which are either large railguns that fire 8,000 ton depleted uranium rounds at 10% the speed of light or a variant which uses two omnidirectional laser canons that at full power could potentially make a planet the size of mercury be destroyed. The first space elevator is complete with follow up completion of others as they were made for the easier flow of materials into space for them to be transported across colonies, or used by the orbital shipyards.

2040: Population of the UNE is now 45 billion people as the Proxima and Alpha Centauri systems reach a population of 250,000. UNE sends colony ships to 15 star systems

2043: The public is introduced to the Bird of Prey a drone that could be controlled by a soldier or be autonomous as it has resembles to that seen in Star Trek. It's roles is that of recon, air support for ground troops, air superiority, and act as a bomber. It is equipped with two plasma miniguns, two light laser cannons, eight AIM-18s and three GBU-41s. Defensive systems is an energy that can withstand up to 19 kilotons. Goliath UGV support vehicle is put into service as it 6x6 wheeled ground drone to support infantry with it's plasma minigun and grenade launchers installed. A quad rotored drone was also produced for infantry to use as it fires a light plasma gun.

2045: The new Zeus Class Destroyer is commissioned into the UNSF Navy. Measuring at 1209 meters with sublight speeds going at 61,000 mph and top FTL speed is Warp 1.5. Crew is made of 104 officers, 400 enlisted, and 900 marines. Armament is dual railguns that uses 700 ton Depleted uranium to be fired at 3% the speed of light, and two omnidirectional laser canons, six 50-megaton warheads, and five 10 gigaton bombs. Secondary weapons is 14x triple railgun turrets firing 14in. at 0.36% the speed of light, 15x twin turret lazer cannons that shoot out 245 megatons of force, and 15×20 Viking II missiles. Defensive systems is are an energy shield that can withstand 269 gigaatons of energy, 30 feet of titanium A armor. seventy 40mm bofors gun, and new missiles that intercepts enemy aircraft and incoming weapons called the SM-12 which there are 16 pods with thirty missiles each. Air wing consists of thirty FX-40 Meteors and fifteen T-280 Valiant.

2049: Soldiers are being issued with combat capable exosuit as they increase the user's strength, speed, and endurance as they could carry up to 2,000 pounds and sprint at 30mph. An armored power suit was also developed in conjunction Called the H.I.A.T ( Heavy Infantry Assault Trooper) it protects the wearer from all small arms fire with a portable energy shield and a built in trophy system as well as titanium plated armor. It's weaponry consisted of a plasma minigun located at the lower portion of the arm, rocket pods and a 50mm railgun located on the shoulders.

2056: The production of the MBT-5 Rommel is started. The Rommel was designed as a main battle tank capable of fighting in all sorts of environments with when an interstellar war broke out and that the service life of old 3rd and 4th gen tanks that were heavily modified were coming to an end. The tank weighs 56 tons with a top speed of 49mph as it its design bears resemblance to the M1 Abrams and Type 10 tanks. It has three crewmembers which is a driver, gunner, and commander which are all located in the hull of the vehicle. Weapons consists of a 125mm railgun firing at Mach 12, coax. 50 cal. MG, two rocket pods that hold up 4 guided rockets, two plasma guns, and a 20mm autocannon. Defensive systems include an energy shield that can withstand 20 Kilotons of force and trophy system.

2063: Second Contact War. Unknown ships that are going at near lightspeed are detected in the Worf and Procyon Systems. UNSF Navy sent corvettes to investigate which they intercept and hail them but the unknown vessels ignore them and open fire which barely scratched the UNSF vessels which as a clear sign of aggression UNSF ships open fire and obliterate the unknowns with one surrendering as it was heavily damaged. They species are called the Rulark who like the Exilan find and enslave every species they find as they have conquered 80 worlds and have a feet of two thousand warships. UNE has trouble deciding whether or not to engage as they know where the enemy is and that the overall technological advantage and likely support from their slave population but not the numbers. Soon it was decided for the go ahead to war.

That the UNSF would attack and hold star systems that are closer to UNE space and have large slave populations and large industrial and other economic importance. Fourteen stat systems are chosen as stealth ships would insert Special Forces that would gather intel and find and destroy any weapons that may be capable of destroying their ships and alert the slave population of what is going on and give them weapons to aid in a revolt.

Soon it began UNSF vessels attacked the Rulark colonies as they destroyed entire fleets with ease as they fired on major military installations weakening defenses as troops began to land on the surface as then major slave revolts began across the. With a highly superior foe against them and a slave population rebelling that Rulark forces on the Colonies surrendered. While that was happening several destroyers made their way to the Rulark homeworld which when arriving obliterated any vessel that fired on them, and attack anything of military value on the surface of the planet as then they warped back to UNE space.

The operation was deemed a success as soon after a message coming from the Rulark homeworld that told they were willing to make peace with whom ever just attacked them. A task force was sent to a remote planet with a delegation for the signing of the treaty. That it was declared that the system taken by the UNSF would leave from the Rulark Imperium, slaves are to be treated more well, Rulark people on the colonies would be sent into Rulark territory, a demilitarized zone would be created between the borders of the UNE and Rulark Imperium.

That after that when humanity began to focus their attention in helping out the slave population that Earth began to notice that some of the aliens resembled that of humans which was a big surprise. When vaccinating them and injecting nanobots that a DNA was done to which a 73% match was made between the humans of Earth and the supposed humans that were under the Rulark.

After that the former Rulark worlds were given the freedom to make whatever governments they wanted as some created their own nations while others wanted to join the UNE. That in response UNE Council accepted their request as work began for a more interstellar government instead of an interplanetary one which had a few representatives of colonies.

2065:Colonial Administration act is passed as to restructure the way a Colony's government would work. That a Colony would have a Governor that would be elected every five years to govern that colony as his power is decided on the votes of his people, as he would work with a Senator that would election would come every 4 years as he would represent the entire star systems that the colonies make up in the UNE Senate. The UNE President would run the country in a similar fashion to that of the US as he can select his own cabinet to advise in certain issues and be elected every 5 years with a two terms.

2068: The 50th of anniversary of the Exilan invasion of Earth takes place as Humanity remembers the fallen but celebrates the achievements such as reaching population of 150 billion and total amount of colonies being 160 planets and moons.

2073:The launch of the newest UNSF warship the Euphrates Class Carrier. Up to 2432 meters long with sublight speeds being 56,000mph and go up to Warp 2.01. Crew Compliment is 480 officers, enlisted 970, and marine force of 2,000. Weapons is two railguns that fire 1,000 ton depleted uranium slugs at 4.7% the speed of light and two omnidirectional laser canons similar to the ones used on the defense platforms, eight 50-megaton warheads, and ten 10 gigaton warheads. Secondary weapons are 14x triple railgun turrets firing 14in. shells at 0.6% the speed of light, 15x triple turret laser cannons that fires 305 megatons of energy, and 20x30 Viking II missiles. Defensive systems are an energy shield that can withstand 300 gigatons of force, 40 feet of titanium A armor, one-hundred-fourteen 40mm bofors, 44x30 SM-12 missiles. Air wing consists of one-hundred FX-40 and thirty-four T-280 Valiant.

2077: For better precaution against invaders that would try to steal and copy Earth's and its Allies technology that a self destruct code is enacted into all technology used from the simple phone and watch to an entire warship. A new precaution code is made for captured civilians that nanobots would now protect the host by having some of itself leave tbe body and enter the body of a person doing physical harm to its host such as torture for information by destroying the invaders heart or other vital organs.

2080:New dropship is revealed called the T44 Comanche. Top speed is 31,000mph with a troop capacity of 46 men. Armament is dual 20mm autocannons under the nose, newly developed saber anti-tank/anti air missiles located in 2 pods with 6 missiles each, and four GBU-41 bombs and a plasma minigun for the tail gunner as it has a shield capable of withstanding 22 kilotons. The Comanche also has a gunship variant that replaces the 20mm cannon with dual 30mm gatling guns, 6×6 saber missiles, and 6 GBU-41 with two door gunners on the sides.

2095: The exploration vessel USS Jeffries discovers a new star system as a world in the habitable zone is found as probes scan the planet for life as civilization is found but very primitive to which under UNE First Contact Laws that the civilization is left alone, and star system is marked UNE territory to prevent the Rulark to take over the planet. That while primitive the civilization could go to different worlds but through something known as the "GATE"