Every single Fire Emblem game takes place on a single continent. Most of the games have no relation to each other, (Outside of direct sequel /prequel games) but have over arching themes, ala Final Fantasy. The formula for most of the games follows:
* There are a bunch of neighboring nations
* One of the nations is ridiculously driven by military, to the point that they are a massive war machine
* The peaceful, idilic nation that the main character lives in is invaded by the war nation is invaded, and usually has it’s shit wrecked in the process. Most of the war nations' commanders of the war nation are stupidly evil for no reason.
* Said war nation declares war on everyone else, because of dark, supernatural forces that are pulling the strings behind the scenes.
* Heroes team of with other nations to curbstomp the evil nation and the forces behind it. Usually with a legendary Sword of some kind.
This was the case in this game, Sacred Stones and Path of Radiance. Blazing Blade and Radiant Dawn followed a different formula.
We will eventually learn all about the nations later in this game. So let me talk about the other Continents
Sacred Stones: Magivel
The unique thing about Magivel is that at one point, it was embroiled in a war between humans and monsters. These monsters were things like Zombies, Floating Eyes, Cyclopses, Centaurs, Gargoyles, Giant Spiders, Gorgons (Medusa’ for those of you who are not fluent in Greek mythology) and Zombie dragons. They were all led by the Demon King. Long story short, he was sealed in one of the Sacred Stones: Five magical stones that are used to protect the nations from the monsters. During the actual events of the game, the monsters were released.
The nations were:
Renais: The main characters’ Erika and Ephiraim’s homeland. Is a peaceful nation that was allied with Grado. Until being invaded by Grado and being more or less shredded in the process.
Grado: The military/evil nation that was at once at peace with Renais, until they broke the peace and started invading. And for some reason, the Grado soldiers commit brutal atrocities upon the Renais people, despite them being former allies.
Frelia: The nation allied to Renais. The heroes spend company with the nation for a good part of the game. Nothing else remarkable, except for them having the most pathetic cutscene NPC’s in the entire series.
Rausten: A religious nation that is essentially Paladin land. The nation is home to the bulk of Light mages on the continent, and their actions lead to the defeat of the Demon King.
Jehanna: Desert nation protected by it’s surrounding territory. The prince, Joshua, ran away, leaving her mother in charge. The nation was invaded by Grado and betrayed by a crazy stalker.
Path of Radiance/Radiant Dawn: Telius
Telius had gone through almost 800 years of a racial war by the time of Path of Radiance. The continent was home to two races, Beorc, normal humans, and Laguz, people who had the ability to shapeshift into animals (Message to people who make furry jokes: Shut up)
There were three tribes of Laguz:
The Beast Tribes: They occupy the country of Gallia, and consisted of the Cat Laguz, Tiger Laguz, and the Lion Laguz. The Red Lions are the royal family and rule over the rest of the cat and tiger laguz. In human form, their distinct features are their cat ears and tails.
In Radiant Dawn, another beast tribe are revealed: The Wolf Laguz, who live in Hatari, the lost nation.
The Bird Tribes: The bird tribes are the nations of Phoenics, home of the hawk laguz, Klivas, home of the Ravens and Serenes, former home of the Herons, who are essentially a Monk race. I say former because a major plot point is that they were massacred by Beorc 20 years before the events of the games.
The Dragon Tribes: Rulers of the country of Goldoa, and the most powerful of all Laguz. They decided to go all Howard Hughs on the rest of Telius and hid their society from the world.
The Beorc nations are:
Crimea: A peaceful nation that is mostly countrylands. Take a guess what happens to it. It’s soldiers dress in white uniforms. Said soldiers are mostly mounted units
Daein: A snowy, mountain filled land that invades Crimea under the rule of King Ashnard. It’s soldiers wear black. People who have been following me on Gamefaqs, TvTropes and That Guy With The Glasses may note that this is what I got my username, “Emperordaein” from. In Radiant Dawn, it kinda becomes the bitch nation of....
Begnion: The largest nation on Tellius, which most of the story of the two games revolves around. Is a massive empire ruled by the Apostle, the Empress who is tasked with speaking to the godess, and the senate, a group of aristocrats, who as you find out in Radiant Dawn, are some of the biggest douches in the world. Their soldiers wear red.