Queen Nehelenia (女王ネヘレニア Joō Neherenia) of Sailor Moon, leader of the Dead Moon Circus, is named after the ancient goddess Nehalennia.
In the English version her name is spelled Nehelenia. She first appears in Episode 148 of the anime and appears in full in act 37 of the manga, though she appeared as a voice in a mirror starting in Act 35.
In the manga, she is like the dark mirror image of Queen Serenity; the self-styled Queen of the dark center of the moon that existed since the Silver Millennium. She made herself known at the celebration of Sailor Moon or Princess Serenity's birth. Swirling with dark energy, she confronted the Queen who used the Moon Wand to seal Nehelenia inside a dark mirror forever. In retaliation, Nehelenia cast a curse that the Moon Kingdom would fall and the princess would never inherit the throne.
In the original Japanese series, Nehelenia is voiced by Yoshiko Sakakibara while her purified reincarnated child version is voiced by Wakana Yamazaki. In the Cloverway English adaptation, her voice is supplied by Lisa Dalbello. In the musicals, Nehelenia is portrayed by Kaori Ishikawa.