Eurus has an high intelligence quotient and is a master of manipulation. As a young child, she lacked emotion and seemingly the ability to distinguish her own pain, cutting open her arm because she wanted to see how her muscles worked. As an adult, she has slipped between being calm to screaming and, when finally seen, to being a helpless child alone on a malfunctioning air-plane. Eurus lacks typical normal human feeling, but she watches and reads the emotional reactions and emotional states.