" The greatest minds and the most advanced engineering went into its creation. They carved the prison out of solid rock from the face of the
mountains just north of the lake. They sealed it not only with metal, stone, and wood but also with ancient and powerful enchantments. In the end, when it was finished, it was believed to be the most secure prison in the world.”
“They must have had some really nasty criminals back then to go to so much trouble,” Hadrian said.
“No,” Myron replied matter-of-factly, “just one.”
“One?” Alric asked. “An entire prison designed to hold just one man?”
“His name was Esrahaddon. "

― Michael J. Sullivan , Theft of Swords (The Riyria Revelations, #1-2)