The world of TDE fits the basic mold of high fantasy fairly well. The playable races mentioned above all have the archetypical characteristics; dwarfs being greedy and most comfortable underground, elves being haughty, etc. etc. The enemies include the standard sorts: orks, goblins, ogres and undead.
As a rule, adventures in TDE are set on the continent of Aventuria. Before the publishing of 4th edition as The Dark Eye, Aventuria was referred to as Arkania in English translations. A large part of this continent is free land not held by any ruler, but the continent does have a few major nations: Middenrealm, the feudal empire holding the heartland. To its north are the noble republic of Fountland and the petty, hostile kingdoms of Andergast and Nostria, to its west is rich Fairfield.
There are many other nations large and small, fuedal or republic throughout the continent. It is set in the time when the level of development can be compared to early-to-mid medieval Europe, but the size of the continent and the various races means no two areas are alike. Neither in climate – the continent offering the full spectrum, from swamps and deserts to permanently frozen lands in the north – nor in culture – varying from fuedal kingdoms to noble republics, from agricultural societies to slave and trade-based economies.
World – Creatures
Aventuria sticks close to archetypes wherever possible, but does add quite a bit of flavor as well. Small but welcome variations in normal archetypes are the fact that goblins are red-furred, muscular creatures as tall as dwarfs, while orcs are black-furred and yet more muscular. Other humanoid races include the Achaz, lizard-men of ancient culture, and the Holberker, a cross of orc and elf. Another good example of being slightly different from standard is the fact that trolls, huge hairy ogre-like creatures, are pretty intelligent and not aggressive by definition, having once had a rich culture in the mountains.
Other than varying in existing archetypes, Aventuria does have a rich offering of flora and fauna. An old fan favorite is the giant amoeba, a very slow but also very relentless giant blob of a monster. Other opponents you'll run in more often than you'd like are the Linnorm, a six-legged wingless dragon-like creature, and the morfu, a slug-like creature covered in warts that it uses to pelt enemies with poisonous horn splinters.
TDE has a clear delineation in how strong and dangerous enemies are, and whether or not it's worth to fight them. Just hacking your way through the world won't cut it (depending on the game master), and the usual tactic against some monsters, like the morfu, is to just run away.
In particular, TDE has a number of high-level creatures that – if the game master is evil enough to introduce them – you either pray are on your side or you run. This includes all but the weakest kinds of dragons, and almost all types of demons. I have never heard of a party of heroes even surviving an encounter with a three-headed Giant Wyrm, no matter their level. Most game masters won't be all that intent to kill the player characters, but regardless, it's a fairly unforgiving world if you're into doing stupid stuff.
World – Magic
Aventuria is a relatively low-magic setting. Magic items are rare, and this does not apply just to powerful magic swords but even to such “simple” items as magic healing potions. This is a consequence of how difficult it is to make magic items – for an item to have a permanent magical effect on it the creator has to imbue it with part of his own astral energy, not exactly a popular action. The only common permanent magic items are mage's staves and other such tools.
This does not mean magic is unfamiliar to the common man. Different kinds of magic users are quite prevalent, not just in the large mage's guild but also in a variety of other callings, such as druid or witch. The usage of magic is often not appreciated within city limits, but it is pretty much a part of life for most Aventurians.