Who can you be? Well anyone (pending DM approval) ;)
But what is in the world that can help you design a character? Lots. Lets use the map provided in the maps link here and I will go over the regional areas and cultures. Culture is important because the same class from different cultures will play very very differently (human fighter Viking vs human fighter knight vs human fighter martial artist, etc etc).
Western continent first: continent is names Ladros.
The NW is a elven kingdom of Tangwen. Cerebral, astute, and secretive, the Tangwen keep to themselves in their quiet corner of the world. They have the best educational programs, largest libraries, and oldest elves known. Sort of like a Lothlorien here.
West is the peninsula gnomish kingdom of Cynwas. These small communities of gnomes do a lot of farming and agriculture. Aside from trade out of their north port town, not a lot of activity happens here. Legends say that during thr War of the Dragon God- giant gnomish war machines came out of the west… but there is no sign of proof now. Feels like the Shire here.
The central is a human kingdom of Managon. The dessert kingdom of Managon is a bustling place. Textiles and trading with the eastern continent all happens here as Managon is the western defender of the natural land bridge. Very middle eastern / Constantinople flavor here in this kingdom.
South Central is human kingdom of Rhiogan. The massive expanse of this kingdom, and the bulk of it countryside, lends itself to its natural resource: horses. The best riders come from here, and most of the worlds horses do too. Picture a Rohan, only not dickbags ;)
Then the southern human Kingdom of FFdor. This was once a great kingdom. It was hit extremely hard during the War of the Dragon God. Its nothing more than squatters and a few small communities now. It used to be a very English style kingdom (castles, keeps, Tudor houses and the like).
South of Ladros is an island continent called Neldoreth.
The Dwarven kingdom of Medrawd resides here. Very secluded. They have great mines in the mountains and have an impressive marine trade for their goods. So picture a sea fairing Moria culture.
North of Ladros is an island continent called Telumendil Isles.
The elven kingdom of Gwyngodyfron resides here. They are keepers of the old world here. Very rustic, Celtic, druidic and natural. The islands are ripe with fey and magic. These emerald islands never seem plagued my the troubles of the world. They keep to themselves, do a little trade, but guard their boarders well. This is like the Fey plane of 4e here, or magical Sidhe isles around Avalon.
Between the two main continents in the south is an V shaped island called: Andor.
There is a kingdom there called Goluden on the coast of the gulf of Kjordell that is 80 drawf / 20 human. They are seafarers and fishermen, a simple life with a lot of Viking style.
The Eastern Continent! Lovingly known as Helcaraxe.
In the north is Kelfar. This kingdom is "off limits" to players. It is a dead kingdom, protected by the mountains and the elves to its south. Legends say it is home to an entire kingdom of darkness led by an knight risen from the grave. Since no one comes in or out, they are only rumors. Some say that during the last battles of the War of the Dragon God, a massive force of darkness aligned against the world and helped the dragon god almost win.
Under that is Elidyr. This massive ancient forest houses the largest kingdoms of elves in the world. Two main cities reside in the forest one per side of the mighty River Tildaruin (which supplies mosy of the fresh water to several kingdoms). It is here in the eastern woods that the Everdark is looming. Spreading its decay to the surrounding areas.
West central is Gofanon. A mighty human Roman style kingdom. Defenders of the east and guardians of the land bridge. They do well with trade as the western side of the goods exchange.
East central is Tyrrhene. A human kingdom with a lot of oriental flavor and style. Their port towns do well, and their fishing is unparalleled in the Adows Ocean. Shallows is the small port town here of note to some players. Fong Univeristy is the greatest martial art school in the world and resides here on the cliffs overlooking the ocean. Also the great city of Fujitsuma is known for its art and craftsmanship.
Central is Paradore. Here the human kingdom of Paradore is a natural cross road. Its very diverse and the closest thing to a "D&D" kingdom you can find- especially in "The City" on its coast. Mixed races, lots of trade.
South west is Synoc. Beneath the southern alps the human kingdom is a life of hard work. They suffer at the weather coming from the seas and from the mountains. Easten European feel here. Livestock, brewing, farming, harsh weather, and good old fashioned toil.
South east is Gweirdathar. A dwarven kingdom living off the land. A mix of cultures here- the Synoc and the Tyrhene have blended with the drawf making a unique blend of farming, crafting, pony riding, and river trade.
That leaves one island in the south east. Dor-lomin.
Its a desert island. Essentially devoid of communities save for a few Egypt style towns on the northern peninsula.