Ermes Costello emerges as a pivotal character in the sixth installment of *JoJo’s Bizarre Adventure*, deliberately incarcerating herself at Green Dolphin Street Prison to exact revenge on Sports Maxx, the gangster who murdered her sister Gloria. After Gloria’s testimony against Maxx led to her death due to police inaction and his lenient sentence, Ermes engineered her imprisonment to confront him, anchoring her narrative arc in relentless vengeance. Shaped by a poverty-stricken childhood in a family-run restaurant, Ermes developed a pragmatic, hardened demeanor. Her fraught relationship with Gloria, marked by resistance to familial duties and aspirations for college, dissolved into guilt-fueled obsession after her sister’s death. She staged armed robberies to secure her place in Maxx’s prison, embodying ruthless determination tempered by street-smart tactics, vulgar wit, and fierce loyalty to allies like Jolyne Cujoh. Her striking appearance features braided hair accented with barrettes, triangular facial tattoos framing her eyes and chin, and a muscular build clad in a sleeveless jacket, turtleneck, tracksuit pants, and arm warmers. Surgical alterations to her breasts—used to smuggle money—highlight her cunning adaptation to the prison’s black-market economy. Ermes wields the Stand Kiss, a humanoid entity that duplicates objects via lip-shaped stickers. Removing these stickers triggers violent mergers, damaging targets. She exploits this ability ingeniously, healing wounds by duplicating body parts or ensnaring foes. Her combat style merges Kiss’s power with raw endurance, embracing self-inflicted injuries to secure victories. Her alliances blend loyalty and utility. She mentors Jolyne, sharing survival strategies while masking her vendetta. Though initially wary of allies like Foo Fighters, she collaborates against shared enemies, fostering mutual respect with Emporio Alnino and Weather Report. Her climactic showdown with Sports Maxx culminates in near-fatal injuries after dismantling his zombie-summoning Stand, temporarily removing her from the fray. Ermes meets her end during Enrico Pucci’s universe-resetting time acceleration, disintegrating in the chaos. The reset reality births an alternate incarnation, Eldis, untouched by tragedy—her family intact and Gloria alive. Eldis joins a familiar group, including Emporio, with no memory of her past, embodying the narrative’s exploration of fate versus self-determination through her dual existence.