Ephnel, real name Marie, is a Blood SoulWorker who rivaled Suzie and was locked away in Ruin Fortress due to the Resurrection Project's failure. She becomes a Soulworker by absorbing SinForce from Phlema's horn and Naomin which were used by the Soulworker unit to reboot the Resurrection Project.
Marie was born in Southern Cloudream and lived with her family before the appearance of the Great Void. The Great Void appears at a young age for Marie and the citizens of Cloudream plunge into poverty. Marie had her candy stolen by her best friend, a pickpocket stole her allowance and she was sold by her parents to a researcher. She ultimately ends up being a research specimen for the Blood SoulWorker project and is subjected to torture and cruel experiments.
Eventually, Marie become a successful Blood SoulWorker with the strength to rival that of Suzie and was moved over to the Resurrection Project. Marie was intended to act as a power source for the project in order to allow the creation of a parallel world and the ability to travel back in time. She refuses to cooperate with the project, causing the project's failure and was locked away in the Bounded Room using a vast amount of Pike to suppress her SoulForce. She was then branded as Failure Number EL (Fn. EL). Her final thoughts before her forceful slumber was for another chance to change the past. Within a week after Marie was sealed in the Bounded Room, Suzie goes on a rampage and kills a majority of the scientists within Ruin Fortress, causing Marie's records to be completely lost.
During the events of the West War arc, Abel is able to discover the top secret Resurrection Project and deduced that Marie, a Blood SoulWorker was still sleeping in the depths of the Ruin Fortress. However, since Marie was suppressed using large amount of Pike, the risk was high that Marie could become a powerful SoulDreg if she was somehow freed. Forced with the choice to deal a potential dangerous threat, the SoulWorker unit makes the choice to find Marie and find a way to stop her potential SoulDreg transformation. Medo was able to discover about the project as well using his newfound abilities to access Ruin Fortress's system and makes his way towards the project.
After defeating Medo, the group makes their to Bounded Room which was found by Naomin. In order to save Marie, the Resurrection Project must be rebooted but Marie unconsciously refused to cooperate. Lex makes the suggestion that they should use SinForce to power the project since SinForce has the property of influencing a person's thoughts. Chii initially offers to act as a battery source for the Resurrection Project but is stopped by the group. Naomin instead offers to use a fragment of Phlema's horn instead to influence Marie and reboot the project. As the group started the project, Medo interferes and is able to cut off the main power supply to project and puts Marie in danger. Faced with no other option, Naomin decides to entrust the SoulWorker unit to defeat Kant and uses her body as a substitute to power the project. The project is successful allowing Marie to be sent into a parallel world in the past but Naomin perishes in the process. Due to the absorbed SinForce from Phlema and Naomin, Marie is able to become a true SoulWorker.
Marie reawakens in Candus City during Kairon's invasion and is unaware of her current circumstances. She then decides to discard her old name and goes by the name of Ephnel based on her experimental failure number EL(fN.EL).