The Yellow Fortune is one of the companies that make up the Mining Consortium. Only female players are allowed to join this company. Male players may instead join any of the other companies, including The Brown Engine which exclusively hires males.
During The Giant Dwarf quest, you can choose to help this company by gathering materials, primarily ore and bars, for its head secretary. After which, you can do some tasks for the director. The director will then let you join the company as a member, so that you can choose her to have a stone head of her image carved onto the giant statue that is in the middle of keldagrim.
Also, in Forgettable Tale..., you can ask her to help you remove the boards blocking a railway tunnel.