Enki is a supporting character in the anime Momokyun Sword who serves as one of the four oni commanders, known as the Four Heavenly Kings, under the demon king Jakioh. She is notably the only female among this elite group. Her allegiance is to the oni clan and its stronghold, Onigashima, where she operates as a key figure in Jakioh's forces.

In terms of personality and motivations, Enki is defined by her deep devotion to Onihime, Jakioh's daughter. She constantly worries about Onihime and cares for her with the affection of an older sister, treating her as a beloved younger sibling rather than just a princess to be protected. This maternal concern is a central aspect of her character, driving many of her actions. Despite her loyalty to Jakioh, her strongest ties are clearly to Onihime. When the truth of Onihime's tragic past is revealed, and it becomes clear that Jakioh had manipulated his daughter for his own revenge against Heaven, Enki does not waver. She remains steadfast, openly declaring that she will always accept Onihime as their princess and friend, regardless of her origins or what her father thinks. This moment highlights Enki's capacity for genuine loyalty and compassion, setting her apart from her villainous comrades.

Enki plays a significant role in the conflict between the oni forces and the protagonist, Momoko, along with her allies. She is frequently involved in battles and skirmishes, including a confrontation against the celestial maiden squad. Her combat style is distinctive, utilizing a whip as her primary weapon in a signature attack. This fighting method, combined with her position as one of the Four Heavenly Kings, establishes her as a formidable antagonist with considerable power. Her personality also has a playful and somewhat sadistic side, as seen when she interrogates a prisoner in a suggestive and teasing manner, a scene that her companions worry will cause complaints if taken too far.

Regarding her development, Enki does not undergo a dramatic transformation of allegiance, but her loyalty is tested and solidifies. Her character arc reinforces her role as a protector. Her key relationships are with the other oni leaders, including Genki, Tekki, and Youki, as well as Jakioh, but her most important bond is unquestionably with Onihime. Enki acts as an emotional anchor for the princess, providing support and reassurance in the face of harsh truths. The narrative uses Enki to demonstrate that even among the oni clan, there exists genuine care and a sense of family, contrasting with the purely malicious ambitions of Jakioh. Her notable abilities include her proficiency with the whip, her tactical command as a leader, and her resilience in combat against powerful foes like the celestial maidens.