The Encephalithid did not have absolute authority over the community; instead, it led the Elder Concord and had an active role in the governing of the community. Its psionic powers were at a level unmatched by any other non-divine being in the Realms.
The Encephalithid had lived for millennia.
During the Time of Troubles, Ilsensine manifested and used the Encephalithid as its avatar. After that occasion, the Encephalithid retained the pair of tentacles commonly associated with the avatar form of the Tentacled Lord.