Hera is a human servant of Swayne. From her appearance in Episode 28 she appears to be some sort of Diviner, but he also took her into battle (if you can call it a battle) in Episode 50.
15 years ago he had her brought to Old House as his daily meal, but she said or did something that intrigued him and so he promoted her to person and had her educated by his lieutenants. As she's now a respected lieutenant, this clearly worked out quite well.
She is never seen without an Eyeball Man.