Earth-54

Earth-54 is a reality in the multiverse.

History
At some undetermined point in this Earth's history, giant monsters began to appear to threaten the Earth. Born from a combination of unknown magics, super-science, and extraterrestrial forces, these beasts, known as "Behemoths", "Titans", and "Kaiju" among other names, became a threat to the human race. To combat said threat, the nations of the world created giant robots and other hi-tech defense forces with which to battle them.

However, not all of the Behemoths were evil; on the contrary, some were there as guardians who would defend humanity rather than crush it. And likewise, not all of the nations of the world intend to use their new weapons responsibly. Thus, in the war between robots and monsters, who is good and who is evil is not always as obvious as it appears.

Setting
Earth-54 is well-accustomed to battles involving colossal titans by now. So much so in fact, that much of society now revolves around it; the left-overs of slain monsters become museum attractions, gold mines of natural resources, and even in some cases makeshift living spaces. Toys and video games have been made that let children act out history as fantasy. There's even been attempts to make movies of these battles, but so far they haven't gotten off the ground.

Numerous major countries around the world have a designated robot champion with which to battle the Behemoths, but because the nations of the world are still not at peace, these robots sometimes end up battling each-other depending on the rivalries and animosities that are dominant at a given time. Likewise, the Behemoths themselves are split on what to do about humanity; some desire to protect them, others their own kind, and finally the most malevolent seek to rule or destroy humanity. Further, islands have appeared in some parts of the world where the Behemoths and Titans lord over a mix of unusual fauna and humans who have willingly turned to worship them as gods they know for a fact exist.

Notable Inhabitants
Humans:
 * Sergeant Caleb Daniels: An ostensibly hard-nosed American sergeant who tends to favor doing things by the book, but also advocates peaceful cooperation with the Behemoths who are willing to defend humanity. He pilots the American Mech "American Dream".
 * Brigadier Charles "Chip" McPherson: An outgoing, cocky, but principled young man who achieved a high rank in the RAF in record time. Although that accomplishment has gone to his head, McPherson nevertheless takes defending his home seriously, and shares Sergeant Daniels' belief that the friendly Behemoths should be accepted as allies. He pilots the English Mech "Golden Lion".
 * Georgios Papadakis: An older man who is nevertheless a capable pilot in his own right. The "veteran" of the mech pilots, he is well respected by nearly all of his fellows and generally treated as the first among equals. He pilots the Greek Mech "Sword of Ares".
 * Amelie St. Just: An attractive but somewhat frivolous Frenchwoman whose already had two divorces and is liable to have a third. A celebrity over and above what most of her fellow mech pilots are, Amelie is often the poster child for the mech pilots as a whole. She pilots the French Mech "Joan of Arc".
 * Emily McGrath: The youngest of the mech pilots, having only just gotten permission to serve in the field after passing all of the tests given to her with full marks. Emotionally closed off and has yet to loosen up as a person, but she looks up to her older colleagues. She pilots the Irish Mech "Black Banshee".
 * Monica Prinsloo: A fairly new mech pilot, replacing her predecessor as the representative of her country, and piloting an upgraded version of a mech that had previously been destroyed by Dark Tyranno. Said mech is the Namibian Mech "Green Thunderbolt". Due to what happened to her predecessor, she is less willing to accept assistance from any Behemoth, viewing all of them with suspicion.
 * Eun Da-hye: A runaway from North Korea who sought refuge in it's democratic neighbor. Possessing incredible intellect, Eun used her brainpower to improve the design of both her country's mech and other's, making her invaluable to the conflicts with the Behemoths. When she proved just as capable a pilot as she was an engineer and mechanic, she was promoted to pilot. She pilots the South Korean Mech "White Cyclone".
 * Fyodor Vanko: A totalitarian brute who unthinkingly carries out the desires of Russia's autocratic government and fights his fellow mech pilots almost as often as he does the Behemoths. While generally lacking in free-thinking, he is no simpleton where mechs are concerned, being a very capable pilot and making for a formidable foe whether he's going against a Behemoth or a rival mech. He pilots the Russian Mech "Perun".
 * Fong Thao: The ruthless representative of China, he cares less about protecting the other nations of the world and more about advancing the agenda of his country and accumulating power for them. He fiercely opposes cooperation with any of the Behemoths, and instead advocates for killing all of them or else finding a way to turn them into weapons for humanity. He is unpopular with the other Mech pilots and in fact has fought several of them over the years. He pilots the Chinese Mech "Black Blade".
 * Ahmed Baz Masih: One of the original mech pilots and like Georgios respected as a veteran. Fairly humorless and grim, but what he lacks in charisma he makes up for in sheer skill and talent as a pilot and a fighter. He pilots the Israeli Mech "Celestial Firestorm".
 * Pilot X: The current designation of a currently unidentified pilot who operates a very unique mech; one explicitly modeled after Dark Tyranno and, accordingly, named "Steel Tyranno" (allegedly was going to be called "Mecha Tyranno" but had to change the name for fear of a lawsuit by an unknown party). Seeming to have an agenda all their own, no one knows what Pilot X is after, and whether they are friend or foe.

The Behemoths / The Titans / The Kaiju: 
 * Primal King Gorgo: Often snidely nicknamed "The Morphing Monkey", Gorgo is the self-appointed "king" of the first of the monster islands that have appeared. Though ostensibly looking like a giant gorilla, Gorgo is in truth far more than just that; he is a shapeshifter, able to alter his size at will as needed, from being roughly the size of a normal gorilla to well over a hundred feet tall. Likewise, he can change his fur color, from brown to white to the color of a silverback. As intelligent as any normal gorilla but also just as temperamental, Gorgo cares little for the affairs of humans or the actions of his fellow Behemoths, and is content to have his own kingdom so long as he is left alone. However, Gorgo sometimes perceives that the actions of other Behemoths might threaten his peaceful seclusion if left unchecked, and so could be persuaded to help fight them if sufficiently convinced. However, this attitude applies as much to humans as it does to other Behemoths.
 * Emperor Kaiju: An utterly massive and terrifying monstrosity, the Emperor Kaiju does not actually seem to reside on any one island specifically, but rather moves from one to the other as well as often staying dormant beneath the waves until roused to action by sufficient force. In appearance it has the build and physique of a gorilla, but far, far, far larger. It also has a head resembling something of a cross between a theropod dinosaur and a mastodon, glowing spikes that run all the way down its back and the roof of its long tail, and finally, what said tail ends in; multiple serpent-like heads that can regenerate if severed. Virtually immune to all man-made weapons, only nukes have shown an ability to seriously injure it, and even these have failed to kill it. Every Mech that has made the mistake of antagonizing it has been swiftly disposed of with little to no trouble, but fortunately the Emperor Kaiju seems relatively unaggressive if not antagonized, and so by this point humans have learned to respect its privacy and leave the placid king to his solitude.
 * Dark Tyranno: Perhaps the most famous of the Behemoths actively fighting humanity, Dark Tyranno is a massive beast that bears not a little resemblance to theropod dinosaurs. But this is no scavenger with tiny arms but a one-beast force of destruction. Strong, durable, vicious, and possessing fire breath to boot, Dark Tyranno has won more victories against both Mechs and his fellow Behemoths than any other. It is said that only Primal King Gorgo and the Emperor Kaiju can beat him, and even the former is not guaranteed. It is perhaps fortunate then, that Dark Tyranno is not consistently an enemy, having sometimes protected humans from other behemoths even as in other moments he attacks their cities.
 * Ebony Wing: 
 * Pterodraketyl: 
 * Sword-Fang: 
 * Iron-Tail:
 * Uber-Raptor:

Trivia

 * The Earth's designation is a reference to 1954, the year the first Godzilla movie came out.
 * The basic premise of this Earth is strongly akin to that of the 2013 movie Pacific Rim and it's sequel, though the designs of the creatures are primarily based off of the ones found in the arcade fighting game Primal Rage and it's unmade sequel, as well as the Rampage series.