Here is my headcanon for the zalgoids and zalgolians in my creepypasta universe "Your Darkest Fears".
Zalgoids are either created by humans making a deal with him or being created by his blood. He can also infect other lifeforms to make them into zalgoids.
Zalgoids come in several varieties, with those either walking on land, swimming in the seas or flying in the air.
Many of the human zalgoids tend to have monstrous forms as a result, while many of the other zalgoids are just created huge.
Many zalgoids come in a variety of colors, although the most common ones are either black, maroon, grey or red.
Their blood comes in a variety of different colors.
Most of the zalgoids reside in the underrealm of Nezperdia, located in the depths of a huge mountain, somewhere far from Old Undertown and Underworld City.
The only way to reach the zalgoids residence is either by teleportation or by rail, considering Zalgo's palace is connected by the Underworld rail network.
Zalgoids have had a long sta