Ceri is a wild wolfblood, a pack healer, and Rhydian's birth mother. From what we know of, she only has two children, Rhydian and Bryn. Their father is Gerwyn. Ceri lost Rhydian while she was hunting for food in the wild, as she left him alone, and when this happened, she knew that she would only find him after his first transformation. She did this using Eolas. Ceri first appears in the episode "The Call of the Wild" when she finds Rhydian and tells him that she's his mother. She's devastated when he rejects her, and it is shown that she may not know a lot of human conventions by the way she acts when she meets him at Bernie's. She obviously doesn't know what coffee is either as she chokes and splutters after taking a sip of it.She looks homeless (and was the wolf that attacked Rhydian in "Mysterious Developments").
Ceri is very insistent on letting Rhydian use Eolas and be a true wolfblood. She holds disdain for the 'Tames', like Maddy's family, because she believes that they are betraying who they are. She invites Rhydian to come and leave with her at the end of episode The Call of the Wild, but he rejects, and Ceri flees.
She reappears in the episode Irresistible, trying to find Bryn who'd left to find Rhydian. We find out that ever since she'd been rejected by Rhydian, she'd been very sad and melancholic. At the end of the episode, due to the chemicals that Shannon and Tom release, she runs towards it as she turns into the wolf. Maddy and Rhydian stop her, and she and Emma have somewhat of a verbal fight. In the end, she ushers Rhydian and Bryn away, and they all leave Stoneybridge to go back to their territory. We can see that Ceri is delighted when Rhydian chooses to go with her.
Ceri shares traits with her son Bryn. They both have brown hair and brown eyes, which leads us to speculate why Rhydian is blonde with blue eyes as Gerwyn also resembles Bryn. Ceri is very loyal to her species, but is not trained in social conventions. She can be quite violent if triggered, which leads back to her wolf-like tendencies.
In the series Ceri serves as a fountain of traditional Wolfblood culture, having knowledge of many ancient customs, as well as speaking Welsh and being able to read runes and Agenspraec.