Helene is a witch who's trapped in a portrait in the Demon Lord's Castle. She is first introduced in Lesson 7-12.
Helene was a witch whose beauty attracted many men, including angels and demons. She was then seduced by Asmodeus and had an affair with him. Because of that, a war broke out which destroyed the country and she was proclaimed to be an evil woman. As a result, a sorcerer named Demetrios, who was the nephew of her former lover, sealed her inside a painting.
She spent hundreds of years trapped and blamed Asmodeus for her fate.
For reasons unknown, she ended up in the Devildom and placed inside the castle. It was presumed that she kept to herself since no one knew the portrait could speak but would suck unsuspecting patrons inside her portrait.
During the retreat, Diavolo, the brothers, MC, the angels, and Solomon were touring the castle and learning about its history when Helene recognized Asmodeus and unleashed a scream that brought everyone's attention towards her. She then lashes out at him but Asmodeus is unremorseful for he does not feel guilty about the damage he caused to her, even openly flirting with her.
- She's likely based on Helen of Troy, who was also known for unparalleled beauty, and also had a lover before entering an affair that led to disastrous consequences.