The Arch-duchy of Telxerxes is a realm is western Forosth with Hyslur-Zemark as its capital. Despite the name, the realm has never encompassed the now ghost-town of Telxerxes east of Hyslur-Zemark. It is ruled by the Arch-duke, presently Bacchante. As with Hyslur-Zemark, the Arch-duchy's name to fame is the cult and legend of Aegyptus Juvens, pilgrims of whom provide the relam with most of its income.
The central part of the arch-duchy is dominated by teeming jungle, and both rainfall and storms are common. It is a hot and humid land unsuitable for most kinds of agriculture other than tropical fruits. The only real settlements in the realm apart from Hyslur-Zemark are Taas and Xats. The realm makes no claim on Filiaxe or the Arosd Archipelago just off the western coast.