Yuri Eberwein hails from the planet Eltria. Her parents' work with the Planet Reclamation Committee forged a close association with the Florian family, leading to a childhood friendship with Iris and the Florian siblings, Granz and Elenoa.

A pivotal incident defines her background: she was framed for the massacre of Planet Reclamation Committee members, including Iris's father figure, Phil Maxwell. This occurred during Iris's absence, causing Iris to mistakenly believe Yuri committed the murders. Following the massacre, Yuri was sealed within the Eternal Crystal, an artifact later exhibited at Earth's Allston Sea facility. Her physical form appeared crucified within the crystal during a flashback, restrained by tree-like growths stemming from her own magic.

Yuri wields plant-based magic capable of generating trees for attack or restraint, demonstrated when she subdued Iris. She also possesses a unique connection to the Eternal Crystal, granting her potential power over life-restoration processes.

In the events of Reflection, Iris manipulates Kyrie Florian to locate and unseal the Eternal Crystal specifically to access Yuri. Upon awakening, Yuri is immediately assaulted by Iris seeking vengeance for the perceived betrayal. Iris then forcibly controls Yuri, using her abilities to inflict harm on others.

Her role in the narrative concludes Reflection at a cliffhanger; her awakening triggers the arrival of Nanoha Takamachi and Amitie Florian to intervene in the conflict.