Drawing of a nihilgenesis wyvern done for the start of book 3 (I like to have a little illustration of a critter/character underneath the dedication!)
They exist with the single goal of assimilating everything into the lower energy state they originated from, like all nihilgenesis, and have more in common with a dangerous chemical reaction than they do with anything truly living. They specialize in quickly stinging their victims as they rocket themselves past them, and are usually smaller in size.