Guinevere is Liz's special dragon. She is like the queen of the clay dragons. Liz's other special dragon is Gwillan the puffler dragon. Guinevere is said to be making fire with her hands. She kilns other dragons: for example, after Gadzooks' fire tear was shed, she used her fire, along with Gawain's, to help heal Zookie. She is Liz's kilner for the dragons as David proved that there was no kilning oven in the Dragon's Den; as such, she is present when every dragon is made. Guinevere very rarely talks to anyone, and is the most respected of the dragons.

In Dark Fire, Alexa placed Guinevere, along with Gawain, on Liz's dressing table, facing the mirror; in Fire World it was shown that David Merriman's imagineered construct 'linked' to the other side of that mirror.

In The Fire Ascending, when Alexa returns to the bedroom after the timeline restarts, she finds Gwilanna dead on the floor, and Liz and Joseph Henry also both dead. After this, the two dragons tell her that the sibyl attempted to deliver the child prematurely, however his auma had left his body; this resulted in both mother and child dying. Out of frustration, Gwilanna had released the dark fire; the dragons say that she died 'of fear', a sentiment shared by the Ix:Cluster that made its way to Co:pern:ica. It is unknown what happened to Guinevere during the new timeline, though it is likely that she remained, as all the other Pennykettle dragons did too.

When Guinevere opened her eyes in The Fire Within and it sayed her eyes glowed violet and wasn't green at first like the other dragons. Guineveres got her name after their ancient ancestor Guinevere.