Yggdrasil also called the World Tree in the northern mythology is the pillar of the world on which the nine realms are based: Ásgard, Vanaheim, Álfheim, Midgard, Jötunheim, Svartalfheim, Niflheim, Muspellheim and Nibelheim.
Even though it is essential to the equilibrium of the world, no one knows anything about its origin apart from the fact that it is the most ancient tree in the world.
The Yggdrasil set is an adaptation by BamboO of the tsuzurao set.