The factory produces hard, but flexible, steel from the iron ores excavated from the Guia Mine. The steel is then used to make items of daily use, as well as weapons.
There is a special blast furnace called the HF-1. It has a high output design that enhances productivity, but the settings are much more difficult to control due to complexity. Rouca usually handles this blast furnace. It was developed for refining metals that require much higher temperatures to melt than iron. If there is something wrong, the color of the liquid will change. If the temperature is too high, the color is whitish. If it becomes too low, it becomes dark red. Orange is the optimal color.
Many characters return to Guia throughout to request things from the Guia factory where metal is made. This is the town where Rouca currently resides and where Rutice once lived. Rouca is one of the mine's hardest workers. He used one of the few vacation days he received to travel in search of his sister.
Arriving in Guia, Avin and Mile are immediately approached by a young, blonde haired boy who explains to them about the town. Avin mentions he is looking for his sister and the boy initially suggests the Adventurer's Guild, which the group is already a member of. The boy runs off abruptly and a woman appears, who explains she is looking for him to which the group tells her that he ran off. The group heads further into town to look for Rouca at the factory. They run into the boy again, who introduces himself as Rael. He explains that he's interested in joining them and has knowledge of Black Spells as a student of the Sorcery School. After being declined to join, Rael runs off and the woman appears once again and introduces herself as Elenoa, a teacher of the Sorcery School. She leaves after talking to them about Rael and they continue on towards the factory. After being granted entry by the gatekeeper, the group comes across a door where they hear what appears to be an argument at the other end. A man in a mask comes out and stares at Avin with cold eyes. He walks off followed by two other similarly dressed men. As they continue on through the labyrinthine factory, they come to the plant manager Kassel. Avin asks about Rouca and Kassel explains he is on an errand. The group, not deciding to wait for Rouca, offers Kassel to help check the blast furnaces around the factory. They do so and return to the plant manager, who thanks them. Rouca, happy to see them both, mentions that he heard a traveler from Balloa saw a girl resembling Eimelle on the highway and that she seemed to be heading to Koruna Village. Before they can leave town, a girl stops them and hands them a letter from Eimelle that mentions she is living with an old lady in southeast portion of Guia. Arriving at the woman's house, she tells them Eimelle is out doing errands for her and asks them to relax with some tea. Unfortunately, they find out too late that the tea contains a sedative and the two fall unconscious. The old lady turns out to be the black-haired girl in disguise, who then steals Kabessa from them while they are asleep. Madram arrives before the girl can escape and it is revealed she is one of Octum's Apostles. The two fight and the girl drops Kabessa. A few minutes later, Rouca and Rael run in. Rouca recognizes the black-haired girl as his sister, Rutice. Shaken, Rutice runs out and soon after Avin and Mile awaken. Rael hands them back Kabessa and eventually convinces them to let him join the group. Frustrated, Avin and Mile, along with Rael, decide to depart for Koruna to continue their search.