Cernd was a member of Clan Arnskull. In his youth, he was captured by the mind flayers of Oryndoll and bought to their city as a mind-thrall. Cernd lived there for many years as a slave miner until his broken body became too unfit.
He was then selected as a subject for ceremorphosis, which was unusual because dwarves were considered unsuitable for the procedure. In fact, the ceremorphois failed, resulting in an individual that half resembled a dwarf and half an illithid and with the personality of Cernd intact.
Cernd managed to escape back to Iltkazar. Here, thank to the intercession of the high priest of Dumathoin, Bettargh Stoneshoulder, the Regency Council allowed Cernd to live in the city, albeit under discrete but constant supervision.