The Floating City of Menyel - Arcanex was lost during the Age of the Void.
Housing what were among the more prominent Shugenja and Mystically based clans of the Fey-Sirona. Including the investigation into and unlocking of all forms of magic and lost ancient lore. As such, there were rumoured to be several lost forms of magica and skills, some reflecting arts now employed and perverted by the Void.
Though none now survive to recall such lost lore.
Rumours:
1: The origins of Biomantic Magic.
2: Knew about Spirit Magic.
3: Responsible for the rise of the Dracosylph from the purification of the Black Dracosylph and experimentation upon the Ulcas.
4: Guarded by a special form of 'Elemental Samurai', sometimes called a 'Nitenichiryu' in the language of the Fey-Sirona.