I chose to center my campaign in some ways around an ancient apocalypse that is tied heavily to the Far Realm and the entities that reside within it. This is an incredibly important part of this campaign setting may present some of the highest end game challenges for players involved with preventing the destruction of this world to the powers of the Far Realm.
Important Fact #2 - The Not so Far Realm
The meteor that crashed into the material world fell through the stars and originated in the Far Realm itself. Because of the meteor, the Weird exists across the material plane. One of the reasons that this meteor could reach and impact the material world is because of the proximity of the Far Realm to this material plane. The two are growing closer and closer every year. With each passing day, the influence of the Far Realm on the Material plane grows greater and greater. More and more aberrant creatures find their way through portals to terrorize the world. Some nations have already fallen under the influence of the Far Realm, though this collapse may be unnoticed by the world at large. Servants of the greatest Aberrant entities have established major churches dedicated to the worship of the stars and Star Spawn have infested the land. Some of these have power even beyond the gods and the primordials. For that, this land is greatly feared.
What exactly does this mean for players adventuring in the material plane? The close proximity of the Far Realm means that aberrant forces in the world are much more common than in other worlds. Cults of the stars are prevelant and powerful aberrant forces have established across the world.
In summary, throughout this game setting, Aberrant forces are always just a little bit around the corner waiting to mess with and frustrate every effort the players may pursue.