The primary goal of the Imperishable was defending the great fortress of Krak al-Mazhar from all enemies of the Brotherhood. The ranks were filled with slaves purchased as young children and indoctrinated throughout their lives to serve the Brotherhood. Upon reaching an age of retirement, if they survived that long, a mamluk of the Imperishable began training the younger mamluks of the order.
Unique among other mamluk orders who also tattooed their faces, the crimson tattoos of the Imperishable were actually special tattoos of power, granting them useful resistances to fire. Most of the members of the Imperishable dressed in red scale armor and white abas. They wore yellow silk sashes over one shoulder.