Shesh-Jaggune is a name that most wizards will not speak aloud. And while every wizard living knows of some other magic-user who has been taken by the dark god's cult -- a friend of a friend, or perhaps an elderly master who lived near the next town -- very little is known about it.
It's told that Malix of Sangyrine once managed to capture and detain a member of the Shesh-cult shortly after she brutally murdered his apprentice. As he prepared to interrogate the disheveled, wild-eyed girl in a cell beneath his sanctum, she sputtered out a short and powerful incantation that stopped her own heart. Malix had been adequately prepared to defend himself, but he had not anticipated a magical suicide. All attempts to raise her failed. The wizard realized that the girl's soul had fled back to her master and was now beyond his ability to recall.
Knowledge of Shesh-cult activities is pure hearsay. Where they spend their downtime, the exact measure of their skills, even their purposes are matters of debate. It's believed that Shesh-Jaggune grants his disciples the ability to temporarily confuse their prey, thus making it momentarily impossible to cast spells or activate magical items. Even magical guardians have been thwarted in some cases.
Invariably the dead wizard is disemboweled and his magical organs stolen. Additionally, his library and/or spell books are incinerated (even those with magical protections) and his other paraphernalia discarded, sometimes many miles away from the site of his murder.