Niella was the Gatekeeper of the Underworld and Udonna's older sister. She played and important role in the Great Battle assisting the Mystic Wizards during the fight. When Leanbow went into the Gates, he told her to seal the Gate with a spell that ultimately took her life. Only her daughter Clare remains. Like Clare, Niella had anAncient Mystic Mode dubbed the "Shining Moon Warrior". She was also Nick's aunt and Leanbow's sister-in-law through Leanbow's marriage to Udonna. According to Udonna, Niella was a great and a powerful sorceress, but was a bit clumsy at her beginnings just like Clare was in her apprenticeship. Leanbow and Daggeron said that she was a great friend, Udonna misses her sister very much but she says that she is always in her heart.