Yuri Dietrich is a teenage girl with light brown hair typically styled shoulder-length and blue eyes. She is the childhood friend of Mage Bilstein, a bond formed early in their lives. Her personality is bright and cheerful, and her primary hobby is photography; she often uses a video camera to document events, including capturing commemorative footage at Mage's eighth birthday party.

Ten years later, Yuri survives in a war-torn world. She encounters Derrida Yvain amidst the ruins of the Bilstein residence, reacting with hostile suspicion by firing a warning shot before recognizing him. During this meeting, she delivers the significant revelation of Mage's death. Following this encounter, Yuri joins Derrida's group, aligning herself with Vidaux Völker and his adopted daughter Mayuka on their journey. Within this group, she continues to support the others, consistent with her established background and relationships.