The Sythilia was the tunnel that allowed the Aether of Asra to pass into the Realmstar's center and disperse to the rest of the voidspace designated for it, thus providing ancient creation deities access to the energy needed to order the world.

Before Nhera could complete this ordering, an aether-consuming astral wurm sensed the confluence in the Sythilia and dove through it, causing tremendous damage to the Realmstar and damaging the tunnel in the process. This resulted in not only the creation of the Hraen, but the disproportionate dispersal of Aether around the lands of Nhera.

There exists one settlement of under-elves in the Sythilia; Seraelus.