Isabel is a wiry and bright girl with dark eyes, who often follows around Edgar in the grove. She becomes good friends with Edgar and Samuel. Isabel is also known as a talented slinger, using her skills to her advantage in many situations.

In book two, Isabel follows Samuel, Kincaid, and Vincent deep into Atherton, into the Inferno. There, she is stung by a Fire Bug, becoming the only person to have done so and lived.