Aidan is comparable to a lar, a spirit from Roman folklore. In ancient Rome, lares were guardians of the living. Romans believed that their households were protected by the spirits of their heroic ancestors. The belief in lares appears to have been a form of ancestor worship, as Roman households often treated their specific lares as patron gods of their family. Lares were also thought to protect public areas of the city, maybe even the entire city. Shrines were devoted to them and I almost think they were the Roman precursors to Christian saints.
Larvae, on the other hand, were the antithesis to lares in Roman folklore. Also known as lemures, larvae were the vengeful spirits of people who were not given proper funerary rights and/or were not honored by the living. We have not yet seen malevolent spirits in the Ebon City series, but one can expect a number of vengeful ghosts in future installments of the series.
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As a side note, vampires and ghosts both fall within the classification of revenants. A revenant is a person or creature that returns from the dead, either as a ghost or a reanimated body. Originating from the Latin word revanans, meaning "returning," the word appears to be an umbrella term for any mythological creature that could be described as undead, including zombies, ghosts, animated skeletons, and vampires. In some modern fiction, it might also be used to describe an undead entity that doesn't fit into any of the easily recognized categories mentioned above, identified as its own unique breed of undead monster.