Dona, Irvine Lester's younger sister, shares a life with him in a region scarred by hazardous acid rain. She works alongside Irvine in their armored trooper repair workshop, managing customer relations and handling the business's practical tasks. Her discovery that Irvine secretly participates in rigged AT gambling matches, breaking his post-war vow to avoid combat, sparks deep emotional turmoil. Confronting him directly upon learning the truth, Dona voices feelings of betrayal and disillusionment, declaring that the real Irvine never truly returned from the war. This confrontation plays a role in her brother's eventual abandonment of his non-combat stance.

Dona actively yearns for relocation to Daleria, envisioning it as an unpolluted haven contrasting sharply with their current environment. This aspiration represents a shared dream for the siblings' future. Her narrative presence centers on her bond with Irvine, the revelation of his hidden activities, and their mutual goal of reaching Daleria.