A researcher working at the Peace Maintenance Brigade with Fanille. Elessa and her mother stayed in Fanille's mansion in the town of Jaergen as live-ins and she became Fanille's only friend. They both joined the PMB to work as researchers. Elessa's field was ruins investigation. Unlike Fanille, who entered the PMB wanting pure-heartedly to do research, Elessa had a special reason for joining.
She betrayed the PMB by having documents stolen from them during the peace conference and absconding. Fanille was greatly troubled over why Elessa would do such a thing. In actuality, Elessa acted as a spy for Rockbein's company as "Alpha" and was an informant from within the PMB. Elessa's homeland was Neylern and she supported the efforts to restore her motherland. Rockbein's plot was to release a "bioweapon" that was sealed in a ruin. They were successful by baiting the Admonisher to fire at Mount Nostal, where the sealed ruin was, but Rockbein lost his life. This released Ziekwalt, Elessa's ancestor. She went into the ruin to plead Ziekwalt to help them, but he absorbed her energy leaving her almost dead. She was discovered by Zeonsilt's group and taken back to the PMB.
Later she became allies with Ziekwalt and was loyal to him.
Ziekwalt's objective was to kill the Queen Screaper. Therefore after he was killed by Zeonsilt's group, Elessa decided to help them defeat the Queen Screaper by creating a device that prevents the Queen from absorbing energy around her.
Elessa had an ancestor named Claressa who was a Slayer. Ziekwalt was a follower of Claressa. Ziekwalt fell in love with Claressa's daughter, Eleya, and had a family with her. Elessa is their descendant.