Ssessibil Istahvar

Sssessibil Istahvar was a half-fiend yuan-ti archmage who lived in the Lonely Tower in the Savage Frontier in the 14 cenury DR. Despite his home in the north, he was not native to the planet of Toril.

Activities
Ssessibil was often away from the tower in his home in an alternative Prime Material Plane, where the dominant species, like himself, was a race of giant cat-like reptilian bipeds.

Ssessibil, while having very few interests in the Silver Marches, protected his dwelling with the help of fearsome elemental guardians and destructive traps. For him, the Lonely Tower was a secret refuge, a fortress of solitude, where enemies and rivals from his home plane would never have the opportunity to locate him.

History
During one of Ssessibil's absences from the Lonely Tower, its defenses were bested by the wizard Arbane. He then proceeded to steal Ssessibil's treasure and declare himself master of the magical abode. Arbane was eventually thwarted by an adventuring company that beat him in combat and allowed Ssessibil to return to his Torillian home.