Demon Wars

Based upon R.A. Salvatore's Demon Wars Saga, Fast Forward Entertainment made a d20 version campaign settings. The story revolves around demonic forces that have begun to threaten the world of Corona. It is believed because demon Dactyl, who was summoned to this world because of the evil of men's hearts.
He soon gather armies of foul humanoids (goblin, powries, and giants who have fallen under his influence) to attacks human settlements, as well as corrupt many in the human lands bringing chaos and destruction.

The largest human kingdom is Honce-the-Bear (Brits). this is the seat of the Abellican Order. Aplinador (celts) located just to the north, and is ruled by various clans. Behren (Arabic) and To-Gai (Nepal) are located to the south. Much of these nations keep to their own borders.
Unbeknownst to many though are two of the worlds demihimans populations. Powries (dwarves) live far off the coast on Julianthes islands. Like many dwarves they live in clans, but are a seafaring folk. The Touel'alfar are the elven people of Corona. They live in secluded forests scattered throughout the world. The fascinating and unique feature about them is that they have gossamer like wings. These wings are somewhat vestigial in the sense they can only be used to glide, slow a fall, hover for a bit, or to jump higher. This may be a tell tale sign that these elves have a close relation to the the fey.

One significant difference to the world is how magic works. The Touel'alfar for the most part know magic as most other worlds do. However it seems everyone else though is limited between to forms of magic that either come from the Ring Stones (Gem Magic) or the Demon Stones (Earth Magic). The rings stones are a number of magical gems that have been discovered by the Abellican Order that can be used to cause magical effects.
These gems are mostly under the control of the order, but the use and the gems themselves have been found in the possession of other owners. Earth Magic works very similarly to to the use of Rings Stones, however you are calling upon the very spirit of the earth (now corrupted by demons) to empower magical effect. From time to time most practitioners may come under the influence of a demon if they are not to careful. Some sages believe that Earth Magic is just as safe as Gem Magic, it is just that the current states of affairs with the Dactyl have added to the dangers of it.