Worldstree is well named. It runs the length and depth of the Universes, from the Abyssmal Gates in the Roots to the linkages to the Heavens in the Upper Branches. Gates can be opened from either Branch or Root, either Magically (the Damethear) or randomly (the Windlord's lightening). Physically, they look like round black holes in the surface of the Tree, and vary in size. At times, there is an in or outflow of air - Gates can suck you in or throw you out.
Despite living in the Tree, Savants supposedly do not open Gates. They control them, and close wild ones when required. Druids have made reluctant contact with a few other Gate travelling Civilizations.
Celenes also have a extraMythic Magic. They use the alignments of the Celestial Bodies to open Gates, which spring like doorways under their Menhirs. Celene Gates are regular and predictable, though recombinations may not occur for centuries. Celenes have regular contact only with an Ancient Reptilian world under a Dying Red Sun - the Gate opens every decade.
The Dark Elves have always used the Roots of the Worldstree in the summoning of thier Demon allies. Their Capital City is located deep underneath the Tree, built on and around the Roots. The only Myths accessable from such depths are of the Abyssmal Myths, and the Damethear pursue contact heartily.
The Astsantse have bargined away their souls for contact with the DreamLand. The DreamLand is another Myth like Worldstree, on the Borders and Corners of the Universes. It may be the other side of Worldstree - no one have Adventured that far.
Travellers are not common, but
they are always the Center of Attention. They may arrive from any of the
above Myths, or random one, especially from the Lightening Gates.
The existance of these Travellers, and the propency of Worldstree to act
out Legend and Fantasy, gives this Myth its special Nature.