In an attempt to also confront Delacroix for the murder of her brother, Arcia joins her fellow Maidens of the Silver to bring him down. After her sisters, the other Maidens, are killed in battle, she is saved by Sieg, leaving her the only survivor. Arcia lays her sisters to rest and accompanies Sieg on his journey.
Along the way, Arcia learns more about Sieg and about his personal feud with Delacroix. After one particularly disturbing encounter with the evil knight, Arcia strikes out on her for fear that she is a burden to Sieg. Later on, however, Sieg tracks her down and requests her presence back with him to continue their quest.
After tracking Delacroix down to the sight of his ultimate goal to unbind the Three Worlds, Arcia goes through the town in search for survivors while Sieg presses on toward Delacroix. She arrives later in order to try to convince Delacroix to let go of his hate over the loss of Siela. Delacroix, in return, uses his powers to force Arcia to shoot herself in the head, thus killing her and sending Sieg into a mad rage.
After Delacroix's defeat and subsequent revelation of the true perpetrator behind Siela's death, Arcia is revealed to still be alive and only shot in the arm. Arcia tells Sieg that she felt Delacroix's will lessen before she pulled the trigger. Arcia then witnesses Sieg destroy the evil monster, Azrail, once and for all.
After Azrail's defeat, Sieg begins to feel the loss of his two friends, only for Arcia to remind him that she is there and will stay with him. The duo then walk off together toward an unknown but bright filled future.