Gates and Guardians
The Gates of the World are as varied as the Island themselves. As structures they take many forms -elegant arches, blocky doorways, indents in an otherwise smooth façade - but are always made of an indestructible jet black material. They are also uniformly large apertures, able to accommodate 10 to 15 people walking abreast and easily 30 to 35 feet high. There is only one known Gate per Island (or Island Archipelago, like Uldrath), and some few scattered on the surface. Some are within huge intact Ancient Race structures, some inhabit partially decayed ruins, and some stand alone on open ground.
When closed they are seemingly inert matter, and for much of humanity's existence they were nothing more than another Ancient Race curiosity. When opened by the Arcanists, a blue shimmer fills the aperture and one need only walk through to move between connected Islands.
At almost every Gate known to humanity stand some number of Gate Guardians. The Guardians are encased bands of silver or copper holding plated armor onto black scaled stone-hard bodies. Beaked helms, each unique, obscure inhuman facial features and what appears to be leathery skin on oblong and squat heads thatjut forward from between their armored shoulders to point directly at the center of the Gate they watch. Seated in a lotus position around the Gates, they remain unmoved for decades, perhaps even centuries, unless something from the surface attempts to enter an Island Gate. In those rare instances they act, and although the accounts of such events are difficult to understand, they have always defended the Gates from any encroachment by surface creatures.