The world of Teo, isn't too complicated, in the time the story takes place it's still in medieval times but this is due to more so magic development than technological. Much like in quite a few isekai novels due to there being magic, technology stagnates.
Speaking of magic allow me to try to explain how that works now.
Magic runs on magic particles which is basically your mana in this world, for the sake of the story we will say mana/magic particles exist on earth it's just in low quantities so humans never discovered it or how to use it.
Now magic particles exist is nearly every living creature or being, except for a few special cases but that's not important yet in the story. MP runs through various vains in creatures and plants and is absorbed, used, and recycled just like breathing. One doesn't necessarily need MP to live but suddenly being deprived of it or lack thereof would result in a body not being as lively until it adjusts to not having MP, for example people on earth can live without it so if a person on Teo were to be without it, within a week to a month of losing it depending on the persons body type/constitution they will be able to live without it just like a earthling.
To use magic is another story, it is unknown how some monsters learn magic, perhaps it is like a fish knowing how to swim, it just does. However for more intelligent creatures and humanoids they must learn magic through practice and whatnot, on Teo as long as you can learn it and have a good particle count you can use it.
Which brings me to my next point, particle count.
Everyone has a set limit of how much magic they can use if any. For example a person with a low mp count could only use small life style magic if even that meanwhile a person with a high count could be casting fire balls and ice spears at the same time and not feel any fatigue. Some are able to surpass their limits with training and study but not all are capable of it. Summoned hero's by the Goroth royal family can increase their mp count by growing stronger/leveling up unlike normal people.
That concludes my magic lesson now I will move on to the kingdoms and the main/central continent of Teo.
Kingdom of Goroth (current location):
Once the most powerful kingdom in Teo.
Rich history, royal family said to be blessed by gods.
Declined due to famine, plague, corruption, and political strife.
Currently losing a war against Astolf.
Army weakened, king bedridden, and corrupt nobles undermine the war effort.
Kingdom of Astolf (enemy nation):
Eastern neighbor.
Military-focused with advanced tactics to counter magic.
Built power through strict discipline and strategy.
Currently expanding aggressively; seized borderlands and trade routes.
Engaged in an ongoing war with Goroth.
Other Nations:
Kragsfall Dominion (North): a territory owned by a group of dwarves not necessarily a kingdom but also could be thought of as one, based in a GIANT RAVINE/CRATOR in the ground, renowned warriors, expert blacksmiths.
Vastly kingdom, (far East like over seas far): the demon homeland/kingdom, a desert kingdom that values peace over anything
Azren kingdom (South): a kingdom based in and around mountains, masters of water/wind magic.
Bravost (West): Naval merchant kingdom, thrives on trade.
Duskveil Confederacy (Far Northwest): Isolated demi-human tribes; fiercely independent.
There are various small villages and whatnot strewn throughout the lands. As well as a couple that aren't affiliated with any kingdom but we will get to them when we do.
And that's all I got for you guys this time, when it's time to explain more I will do so like this again.