A more clear explanation with some spoilers .

Alright, the very first thing I'll address is why the MC is human.

In Odessa,there are all races. Humans, trolls, elves,orcs,kobolds, giants,ogres. Now consider elves as a superhuman faction of the world. Elves are the only ones who are allowed to use magic and only they can be mages. Before the prophecy, each and every race could use magic including humans but the then leaders of the lands chose to kill off all other races who could use magic to establish dominance of elves. The human body is the most compatible with magic as it can wield even two different elements sometimes. However,the elves are limited with their kind. Like for example,ice elves can't wield fire and fire mages i.e dark elves can't wield water or ice. So the MC has a human body but he isn't exactly human. The elements,all of them came together and formed him with all their powers. The body he got was of a human as they're considered to be the jack of all trades but as our MC only has a body like humans doesn't mean he is one. He is made in such a way to master everything,to be able to wield different, contradictory branches of magic like life and easily and master them completely.

Next comes the information about the kingdoms.

Before the prophecy, elves ruled over every single land. Korg was the then ruler of the fire nation.

At that time trolls and humans were also considered as mages and they lived along with the wood elves, the then rulers of Earth. The wood elves had nothing against humans and they were a carefree race. However, they had oppressed the orcs under their rule. Korg wanted to eradicate every single race from Odessa except for elves. When he went to the wood elves, they refused to kill the humans and trolls under their rule. Darks elves are proudful and hate taking no for an answer. Korg was the King and he felt insulted by the wood elves. He allied with the orcs and promised them power. They overthrew the wood elves. Seeing this water and ice nation too allied with Korg with the purpose of eradicating other races and successfully did so. Trolls were underground and Giants and ogres took to faraway mountains. Kobolds started dwelling in dark caves and humans,well they were simply made slaves of the empire.

Now there was harmony among the elves. The air mages distanced themselves from Korg as they could sense the carnage he would bring. They created their own floating islands and distanced themselves. The high elves,as they're called, remained neutral.

Then, the great prophecy was announced. Korg grew ambitious,he wanted the King of all to be one of his own. Allied with him were the Orcs as he was the one who granted them their lands. The water and ice nations refused to be subjected to Korg and allied against Korg. This resulted in a war which finally ended with the of Korg.

Now, the queen of fire nation is the daughter of Korg and takes after him.

In all of this,the air nation still remains silent. There is still a lot of tension between the nations and the borders remain forever shut.

Now comes the character thing. I haven't given pictures of characters in the start itself as I don't want to reveal them early. However,if you want to see them, please comment below the answers to following things.

Should I add the character sheet in advance?

Is there anything else I should explain??

Is there anything you don't understand??

And all suggestions/criticisms are welcome.

Please do comment.