The Darkness is a big dark cloud which can swallow anything. All it wants is friends. It is turned into "the Kindness" in the end of the final movie by Poof's smile, the Fire Wand in Fairy World, the Wind Wand on the dark side of the blue moon of the V-Gon system, and an Ice Wand on each planet in the solar system (except for Uranus).
Destructinator is the "Lead Eliminator" and the antagonist of the film. It absorbs powers and weapons, and, over time, became very powerful. It was defeated after Timmy pushed the button for his death-inator.
Eliminators are the basic villains in the movie. They can absorb weapons and eliminate people by sucking them into their bodies. In the end of the final movie, they become the "Hugginators".