Janah is an ascended angel first mentioned in Haunted. She was the first angel to be sent after the Nix, but she was trapped in a demention in which time passes slower than in reality. (Every 2 minutes in real time = 3 days in the demention time.) Whoever is in the demention suffers from sensory deprivation. Janah was trapped there for 5 years in real time before the Searchers located her...but by then she had gone mad.
She is described as having a tiny form, being no more than 5 ft tall, with "bird thin wrists" and long dark hair. She was a former witch. Whenever an angel or half demon nears her, she (having gone mad, and traumatized from the last demon she'd face; the nix) senses an enemy and attacks...much like she did to Eve Levine upon first meeting her.