One Ring

From t2twiki

The One Ring is the single most important item in the world of the Two Towers. Anyone who knows of it either seeks it or seeks its destruction. One who wielded it properly would be granted almost infinite power, enough to corrupt even the purest of souls. In particular, Sauron the Dark Lord--who himself forged it in the Second Age--is constantly searching for it. If he finds it, the doom of the West is assured. If the Ring is destroyed, however, Sauron's evil will be ended forever.

Players may run across the One Ring a handful of times during their adventures. Any time this happens, it's a token of achievement and a step toward greater power.