Mavis is the step-daughter of Merle Highchurch. She is described as having straight red hair and glasses.
She acts exasperated by her half-brother Mookie's antics, but she still cares about him and tries to keep him out of trouble.
Mavis expresses some concern over Merle's adventures and does not seem to be inclined towards the adventuring life herself. When Merle suggests that she join him on his adventures in the future, her response is that it "sounds extremely dangerous".