The Starseed, if legend is to be believed, is a relic that was created by the First, the originator, the entity that crafted all existence from the endless void. Perhaps there is only one Starseed; perhaps each plane or universe has a Starseed that was the genesis point of it. No one, save perhaps the First, can ever know.
What is known is that the Starseed has no special powers that can be readily tapped by mortals; rather, it has two very simple, very specific powers that are the source of the name.
In appearance, the Starseed looks like nothing quite so much as a simple seed of milky-white crystal, seemingly polished into the shape it holds rather than carved. It is incredibly hard and strong, and even universal solvents are incapable of damaging it. It weighs perhaps five pounds, and is a little larger than a human heart.
The first of the Starseed’s powers is that, when exposed to the raw emptiness of the void between worlds, it germinates, sprouting an entire new plane around itself. While this seems like a wonderful thing, there is a problem - for several thousand years after this, the new plane is in a state similar to the Big Bang: intensely, insanely hot, expanding at speeds that defy conventional reasoning, and completely hostile to life. Even elves would be hard-pressed to find a way to use this power, but it does serve as a way to be rid of the artifact.
The second power is much more useful to mortals, in some ways. When buried deep within a world, preferably in the very heart of the world, the Starseed will renew the lifeforce and existence of the world. For a world teetering on the brink of destruction after an apocalypse of some sort, the Starseed can be salvation. Similarly, if the world is under assault by some force seeking to destroy it, the Starseed’s power will completely restore the world.
This is not without drawbacks - the renewal is near-total. Cities will be ruined asforests erupt beneath them, mines will cave in as the Starseed’s power renews the veins of metals and minerals that run through them, and the oceans will surge into great frothing torrents as pollution is erased and life restored. In the end, the Starseed may destroy many lives in the process of ensuring the continuation of life itself.