Void creatures make up the armies of Varyn, Hytale's leading antagonist. All void creates share similar features, for example they all have glowing green eyes, pale flesh with purple hints and curving horns. Look out for diamond shapes, as they are said to be a key indicator of the presence of Varyn and his minions.
Each item and mob has its own info page, on which you can find all sorts of information such as crafting recipes, looting information, damage, and more. As we unfortunately do not know all information about Hytale, some information is speculative and may not not not be in the full release of the game.