Fortuna serves as Emilia's aunt and primary guardian throughout her childhood in Elior Forest. Leading the secluded elf settlement guarding the forest's seal, she displays fierce protectiveness, especially toward Emilia. Her significant bond with Petelgeuse (later Geuse) positions him as a father figure to Emilia and implies a romantic partnership between them. When Pandora, the Witch of Vainglory, invades Elior Forest to shatter the seal, Fortuna rallies the elves against the Witch Cult. She confronts Pandora directly in battle to defend both the seal and Emilia. During this clash, Pandora manipulates Petelgeuse into activating the Witch Factor of Sloth, causing Fortuna's accidental death by his hand. This event profoundly traumatizes Petelgeuse, catalyzing his descent into madness and evolution into the Sin Archbishop of Sloth. Fortuna's legacy reemerges in Subaru Natsuki's Sanctuary trials. One trial subjects him to an illusion where Fortuna embodies his mother, accentuating themes of parental love and reconciliation. This sequence exposes Fortuna's influence on Subaru's psychological journey as he processes his past through this fabricated bond. Her proficiency in ice magic and unwavering dedication to safeguarding her family underscore her impact on Emilia's backstory and the broader narrative fallout from the Witch Cult's actions.