I have talked before about using the world created in the books called "DeathGate" series. When I talked about it last time, I thought I would just create a new land in my world where the Sartan and Patryns existed and have some of the main characters around for parties to interact with.
Since then though, I have decided that I would instead have the Patryns and Sartan be two races of extremely powerful human magic users that are now pretty much extinct. All that is left of them are books and enchanted, rune covered items that they left behind.
This places them in the realm of legends and possibly as demi-gods if I still decided to create the "Nexus" where they ere all stranded as a place on the map. In the meantime though, I can create new Patryns and Sartan to build legends around.
The enchanted items will all be top shelf, high level stuff. These two races didn't mess around when they enchanted items. They meant it. You'll likely never see anything below a +3 item with at least one or more truly fantastic features built in as well.
The interesting thing about their left behind enchanted items, at least the way I see them, is that they will almost always be too powerful for even the highest level PC's. Their magic is strong and most often unpredictable. Anyone of any level might find one of these weapons and, not realizing what they have in their hands, unleash some crazy stuff bringing a new aspect to the adventure.
Because the Patryns and especially Sartan did not intend to have the "normal" people be decimated in their war with each other, A DM/GM will have lots of flexibility as to the lethality of the situation in regard to how much damage these things will really cause the party and those wielding the items.
I have already added a "Blade of the Sartan" to my enchanted items list in the WikiMage and I am now working on adding a ship covered with Patryn runes that causes it to fly and maybe even travel into the various Planes of Existence.
Certain Sages in my world have encountered the books that the Patryns and Sartan have left behind and can be consulted (not many and not cheaply) to try to learn the nature of the items they have picked up. As a matter of fact, it can turn into a quest or adventure just to find a sage that can provide the desired information while accidentally discovering traits of the items as they go from place to place.
On enchanted items that Patryns and Sartan made for use by normal humanoids, they always engraved the name of the item in each of the main three or four humanoid languages. This can be a starting point in the road to discovery.