Like his companion Ffion, Cei began his career as a mercenary soldier but chose to follow the druid Baelyrwn. He was smaller, quicker, and sharper than his burly friend, less open with others, more cynical, and disinclined to trust easily. Cei has a particular fear and hatred of spiders. His career came to a terrible end when he was killed by a demon in the dungeons attached to the Shrine of Ningishzida in Caer ap Nos.

Cei was a mercenary soldier under the command of a less-than-honorable captain, Cei was one of the few characters who survived an assault on the lair of a swamp hag.  After the death of his captain and two of his fellow mercenaries, Cei found his loyalty amply rewarded and he soon became a staunch follower of those who had hired his former captain.  Cei followed his patrons into many adventures, and his life was saved by them on more than one occasion.  Most memorably, he was revived by the druid Baelyrwn after nearly dying from the poison of a gigantic spider.  After this, Cei was devoted to the druid, following him on an adventure against yet another vicious hag in the Black Mountains.  He finally met his end when he ventured into the dungeons of Caer ap Nos, where he and his companions found a lost shrine to the demon lord Ningishzida.  Cei and his companions slew a powerful naga and many stone statues of serpent men, only to be torn to pieces by a vulture-headed demon further in the shrine.  As Cei's companions were all running for their lives, his body was never recovered or buried.