Heidi was born to be a rebel, she broke away from her parents' discipline when she was a student and began to be self-reliant. She is obsessed with machines and believes that machines are more reliable than people. After the phenomenon, she saw a husband kill his wife. She was betrayed by a friend, causing serious injuries to her body, and modified her body through machinery. Heidi who is the first character you meet who helps you during your first stages and helps you build up your home base.