GATE: Thus kroxonican republic fought there (Male OC X GATE: JSDF)

In World War II, The kroxonican empire attack the allies and axis powers with advance technology. Many nation from both allies and axis decided to work together to stop this alien threat. The earth nations developed a weapon to weaker this invaders. After 4 months, 56% of the kroxon species population have been destroyed has many of them couldn't handle this human new weapon. The kroxon army surrender after learning this weapon will destroyed their species. The species told the humans their origins where the last species when they're planets has ran out of resources, which result of the many wars to take the last of resources on their planet. However they're didn't aspect humans living there, Seeing humanilty has a threat they're decide to invade it. Which result of losing. The human government where completed shock that the kroxon where leaderless and no way. United States, United Kingdom, Nazi Germany, USSR and Empire Of Japan demand the alien species hand over their technology. Leaving no choice, They're gave many advanced tech to the humans. The kroxon species fled to america, africa, middle east and asia continents made it their new home. They're created the kroxonican republic, However, The kroxons mobilized their military with human blueprint from WW2 and Cold War era, They're were not advanced as the humans. They're didn't to involve this new war. In 1969, A mysteries roman struggle appear in the capital of kroxon capital, When roman army attack them, When the kroxon repelled them, They're send their military to the other side. However, They're is a second gate from the JSDF came from. How will the JSDF, UN, and the rest of the modern world react to this new species that came from the earth 60s? Will they're been peace between kroxon and this..... parallel humans?