Yang Gui the "Vacant" is one of the elite generals of the Ancient Father's Cabal, as well as a necromancer. Her homeland is China. She first appears in Cape Town, after having learned that the Royal Exploration Agency would be sending a messenger there. Upon meeting the hero party, she travels with them to the Eterna Mines to help search for one of the 7 missing tablets. Once there, however, Yang Gui reveals her true colors and attacks the party.Yang Gui makes her second appearance at the Nirvana Palace after Edward Brown and company have finished battling Astell, who was brainwashed into serving the Ancient Father's Cabal after becoming separated from her sister, Scarlett. In desperation from her defeat, Astell quickly paralyzes the party with her magic, which allows Yang Gui to cast her finishing attack. Astell's concentration is momentarily broken, however, when Yang Gui decides to casually kill her along with the heroes, which allows Scarlett to break free from her sister's hold and knock her away from the blast. Seeing this act of courage and sacrifice from her sibling breaks the spell that had been put on Astell, and she then joins the four heroes in battle to finish off Yang Gui.
It is revealed later on in the game that Yang Gui had attempted to murder Pad as an infant, along with his mother, during her search for the Talisman of Light which had been held by Pad's father, Patrick. However, this attack was thwarted thanks to the hero party's intervention via a side quest involving involuntary time travel.