Here's a little breakdown of the Homunculus Hidden in my Moon's Absolute fic. I'm gonna tell the Full Metal Alchemist fans to GTFO right now.

READ THIS, PLEASE. I DIDN'T TYPE ALL THIS FOR SHITS AND GIGGLES.
Similar to the Phantom and Animate Hidden, Homunculi are created. They are commonly reanimated corpses, brought back in a similar fashion to the Phantom Hidden with the exception being that the soul refuses to leave the body.

Their physical strength is second only to the Angel Hidden, but are able to withstand battle for longer periods of time due to their inability to feel pain in their dead bodies. If a limb is lost, they will take a replacement from those they have defeated. Vector sports a limb like this and considers it a trophy.

Homunculus Hidden are commonly mistaken for Zombie Hidden in appearance, but unlike their subtype, they do not resort to acts of cannibalism. The Zombie subtype of Hidden also do not reconstruct their bodies and lack self control.

Homunculus Hidden are normally, like many other Hidden, nocturnal. Sunlight has no adverse effects on them, but many of them do not enjoy sunlight.

They are extremely devoted and over-protective creatures, easily creating a strong emotional attachment to a weaker Hidden of their chosing. They will spend nearly two-thirds of their life at the side of whomever they protect.

Vector lives with and fervently protects Honey in a dilapidated building along the Westopolis border.