She a general of the 3rd Order. Her class is witch. She is ambitious and seeks the power that controls the laws of the world.
In a flashback scene, Yelma is explained to come from a poor Elvale family with no opportunities for education or magic studies. She was taken as a protegee by Capehorn, who noticed her outstanding potential. Under Cardinal's patronage, Yelma made her way through the ranks extraordinarily quickly and was promoted to a general of the 3rd Order, much to the surprise and suspicions of the regular knights.
After biding his time, Capehorn approached her with a proposition. Knowing her interest in the Rule that governs the worlds, the cardinal offered Yelma a manuscript containing the details of the Unwritten Law, a copy transcribed before his exile from the Tiamat tribe. In exchange, he requested help with summoning a resident of the Underworld for his own goals.
Shortly before the King's demise, during his visitation of the lands, the two performed a ritual to summon and bind a demon in the halls of Aventheim. The fiend who appeared to them was recognized by Yelma as Zolgonark, the King of the Underworld. In the two days that followed, the witch has entered a contract with the fiend secretly from Capehorn, pledging her servitude in exchange for some of his powers.
Several days after the King was killed, Yelma has called Grand Marshal Gunther into the castle and proceeded to tell that he would be blamed and seen as traitor by the populace for his failure to protect the king. Having cowed the old soldier sufficiently, Yelma persuaded him to take on the royal responsibilities and wear a replica of Wilmgard's battle armor. Unknown to him, the suit of armor was infused with Zolgonark's curse, corrupting the marshal and bringing him under Yelma's and cardinal's influence. The sudden change in Gunther didn't go unnoticed by the citizens and knights alike. Concerned by it, general Reinhart was able to link the transformation to the witch. However, a spy of Yelma's was monitoring his actions, and Reinhart was murdered by the witch herself when he tried to expose her.
Meanwhile, as the cardinal was taking control of the castle, Prince Nordich began to have suspicions about his and Yelma's motives. He came to realize the truth about the plot soon, unaware that he was overheard by the witch herself at the time. In a fit of anger, he confronted Yelma and swore to denounce her. Before he could do so, the witch turned him into a werewolf to stifle the truth.
In the aftermath, Yelma began to grow openly disloyal to the cardinal, refusing to follow his orders or meet her follow generals and accusing Capehorn of hiding information about the theft of king's soul from her. Disturbed by this change, Capehorn ordered Vishna to follow Yelma's activities closely.
After Dotaurus fell at the castle doors, Zolgonark has finally realized the approaching presence to be Wilmgard's soul. After punishing Capehorn for concealing the information, he ordered Yelma to retrieve the King's stolen body. To do this, the witch went into the castle dungeons to see the imprisoned Algiery. She put the king's former lover under a spell of her own and dispatched her new servant to bring back the corpse, following the Tiamat at a distance.
During a track through the Westkin territory, she met the leader of the Mehse tribe, Vilgo, and offered him the power to achieve their vengeance on Wilmgard. Vishna caught up to the witch around this time and accused her of treason. However, the cardinal's knight was struck down by Vilgo, now transformed into a fiend by Yelma. The witch continued into the Tiamat lands, defeating Sacchito the gatekeeper on her way and reviving her again to stall Wilmgard's advance. Within the domain, Yelma came face to face with Algiery once again, who found the strength to break from the mind control. The priestess was killed by the enraged witch shortly before the Wisp came onto the scene.
Although Yelma was the first to reach the crystal prison where the king's body was held, she could do nothing about it until it shattered with Alier's demise. In a moment of triumph, the witch transferred her own soul into her trophy and went on to defy Zolgonark, her former master. However, she was denied the body's full power, and her spirit met its end at the demon's hands.