Listen to the Rain

If you can get a hold of it somewhere, the entire way magic items work in Earthdawn is built around the same premise, to the extent that the way you identify what an ancient artifact can do is by learning about the life of the last person who used it. Mechanically, it starts off with no powers, and as you go along and learn more you unlock its various abilities until it's fully powered up.

It lets you start with the ancient magical weapon of your house and gradually become worthy to wield its true power through the course of your adventurers, which is pretty awesome. I never did like the idea of characters just throwing away their old weapons when new ones came along, "This is my trusty sword, handed down from my father, or at least it was until I found that Sword +2 Flameblade in that ancient ruin"-style.