Yggdrassil

Yggdrassil is a world-tree that appears in the Aeon of the Champion story series, and is the most iconic of its kind in the entire plotline. Central to Yggdrassil is Middle-Earth, the centerpiece of the Universe and pride of all the Pantheon.

Lore
During the Ordering of the Universe, the Pantheon housed all the safe planets on the Plane of Existence inside cosmic world-trees, in order to keep the planets from drifting off into the Great Unknown repeatedly and possibly colliding with other planets in the system. One such world-tree was Yggdrassil, which contained the homeworlds, named so because they were the first worlds in the Universe to contain life. The worlds were ordered, from top-down, then left-to-right, until the world-tree was full. Thus, the chaotic energies of the Creation were stabilised, as the roots of Yggdrassil burrowed into the fabric of the Cosmos itself. So life began.

Infiltration
After the Fall of the Pantheon around -100,000, when the rebellious archangel Sargamon lay siege to the High Heavens with his demonic army, destroyed the Holy Sanctuary and slaughtered the Old Gods, the only thing that had stood between him and world domination was the Fusion Staff. Fortunately, the power crystals making up the top of the staff were blasted into intergalactic abyss by Sargamon's helblast, scattering them possibly across many worlds. Assembling as large an army as possible to scourge all Creation in search for the stones, he targeted - and invariably destroyed - thousands of planets during the Unholy Crusade. Finally, he settled on Middle-Earth, deciding that it HAD to be the right world (after the scandalous arcane exploits of Dan'Ariz and his followers sent magical ripples through the dimensional planes.

In his quest to destroy the planet entirely, Sargamon has torn Yggdrassil almost asunder, ravaging the homeworld over and over again in order to induct as many races as possible into the folds of his Legion. The Giants of Jotunheim are a prime example of this manifesting.

Trivia

 * Yggdrassil is the world-tree in Norse cosmology, and it is also made of cosmic ash, like the one in the AoC Universe.
 * World-trees are stabilisers. When their roots connect to the basement of the Universe, unstable energies become serene.
 * Middle-Earth is one of the homeworlds of Yggdrassil, along with Jotunheim, Muspelheim, Vanaheim (not to be confused with the angelic city), and Niflheim.