The Lance of Marduk
The Broken Realms
In the Dawn War the Goddess Vaalbara tried to escape Yggdrasil with her family into the Far Realms, and while she did make it out she ripped several of the Planes from the Faded Realms outside the bounds of Yggdrasil. Becoming the fallen fruit of the World Tree, the Broken Realms have become just as populace as the Central Realms, especially Midgard which heavily resembles the worlds of the Broken Realms. The Gods of the Broken Realms were the survivors of the journey that their “mother” Vaalbara took them on, now they hold the same power as the Celestial Gods, if only in a smaller area of space.
The Forgotten Realms sits closest to the old rift which removed it from Yggdrasil’s hold. Many of the Gods who rule it control the Heavens around it, while there is still a great deal of connection between it and the Astral Sea and Elemental Chaos, thusly many of the gods remain the same deities as in the Central Realms. The Forgotten Realms also have a version of the Feywild and Shadowfell of the Central Realms, only in this case they are mirror images to the landforms found on its mortal plane.
It is unknown whether Eberron exists on a different clock than Yggdrasil or the rest of the Broken Realms, but it does seem to do its own thing and it does these things well. It bears very little connection with the planes of Yggdrasil, having been formed by three of the gods which fled with Vaalbara. These were three of the godly sons of Io who managed to kill each other, forming the land of Eberron.
The world of Athas, often just called “the Dark Sun”, is the farthest of the Broken Realms. It is so far from Yggdrasil (and the Forgotten Realms for that matter) that the gods cannot interact with it, and it only continues to drift outward into the Far Realms. Life on Athas has become more or less post-apocalyptic, with everything reverted back to a simpler time.
Not much has been heard from Oerth and its deities. Unlike the Forgotten Realms, the Gods of Oerth have no connection with their old kin. It hasn’t been seen in a while, not even by planes-walkers. There are some that think it may have fallen out of favor.