Relic Weapons would be out in the world that you can find. Only one of each and they always drop on death making them risky but powerful to use.
Imagine you find a Sword thrust into a stone. You manage to free the Sword and if you inspect it you see that there is some sort of glyphs or something on the sword. If you figure out what that means it leads to steps to perform. If you do it changes from a Weathered Old Sword to a glistening blade of some unknown metal that burns with a blue flame. It'd have similar ranged but alternative version/effects of a swords normal skills.
The goal of Relic weapons would be interesting and a bit stronger but not overpowering. Something like a Scythe that drinks the blood of enemies during a Blood Moon, so sometimes it's a lot stronger, or situationally it's stronger, but generally it's just another end game weapon or looks cool.
If you die and don't recover it then it enters the world to be found again.