Disclaimer: I do not own the Godzilla franchise or Evangelion, they're both owned by Toho and Hideaki Anno.
Kaiju
A word that has been used to describe creatures of myth and legend all across the world, people didn't think about it much, but that would soon change forever….
The year was 1954, the country of Japan was still recovering from the nuclear strikes on Hiroshima and Nagasaki by the Americans a decade ago, however, that would not compare to the disaster when He came….
A creature towering over 100 meters resembling a dinosaur appeared over the island of Odo, destroying villages and slaughtering the population. In the midst of the attack, the entire island was contaminated by the creature's radioactivity leaving it a wasteland, religious groups dubbed it the Right Hand of God or a sign of the Apocalypse however, the world would use the term "Gojira" given to the Odo islanders and translate it to Godzilla the King of the Monsters!
The creature had reached mainland Japan, destroying cities and the loss of millions of people.
Conventional weapons like tanks, planes, bombs were unable to pierce the creature's hide, obviously nukes were out of the question, until a weapon was made by Dr. Daisuke Serizawa.
Dr. Serizawa found an unknown compound that disintegrates living organisms under contact in water and called it "micro-oxygen" and would put it to use on his device, the Oxygen Destroyer!
He and his colleague would soon dive to Gojira's hideout and killing it with the device. However, Serizawa cut his line of his oxygen and died with Gojira, as he feared his research would create a more weapon terrible than Gojira and harm innocents, so he took the secrets of the Oxygen Destroyer to the grave.
After the incident, a joint Japanese-American unit dubbed Monarch was tasked to find any Kaiju like Gojira. In the following decades, Monarch has recorded, documented and seen Kaijus fight in the world, examples like a pair of giant undiscovered species of pterosaur against a swarm of insects and their queen, a giant ankylosaur that can curl like a ball, a moth goddess fighting her dragonfly counterpart while her twin priestesses are singing to her, a mammalian creature containing unknown gems and minerals, a plant-animal hybrid that can encompass a entire rainforest, apes the size of mountains fighting for supremacy against carnivores with insatiable appetites in an uncharted island, an underwater city depicting stone tables between a turtle, a flying creature and a sea serpent locked in a viscous war, and a carcass of a golden scaled draconic creature frozen in Antarctica, the list goes on and on.
By the time of 1980s, Monarch was officially disbanded by the UN, due to the organization not being of use anymore and seeing as the world was safe from Kaiju, Monarch agreed. However, we were wrong and the monsters would soon return in an unexpected way.
It was the turn of the millennium, the year 2000. An event known as Second Impact occurred dis-tabling the Earth's geomagnetic axis off causing the oceans to turn red, massive earthquakes and tsunamis causing the deaths of billions of lives and the loss of several countries . As the dust settled, a species of extraterrestrial origin code-named "Angels" appeared and had one objective, to destroy humanity. It was time for Monarch to regroup and create a new weapon.
A weapon utilizing the skeleton of the First One as a frame over a suit of armor, dubbed "Project Kiryu".
Maybe this will teach the Angels that Nature can not be controlled.
(AN) Well, that's the prologue to Kiryu vs Evangelion, this story will feature bits of lore pertaining to Kiryu and its pilot named the Kiryu Files. Also, I'll add other monsters to the mix as well and characters from Rebuild and the Original will appearing.
(AN2) As for the SAO fic, it will be put on hiatus and undergo major rewrites and reboots.
(AN3) Extra points if you figure out the list of monsters, I referenced.