The Darkness is the main, later secondary antagonist of Wishology!, and its true intentions remain enigmatic until The Final Ending. Its sole purpose is to alleviate its lonely existence by making friends, but every planet it visits, such as Fairy World and Wonder World, the inhabitants have panicked by its presence, and they blast the Darkness back into space (the only exception was Yugopotamia, which was swallowed into the Darkness without any explanation why, although it may have intentionally did this to lure Timmy out to it).
This ancient being has existed for tens of thousands of years. It was first encountered by the Ancient Fairy Warriors, whom did battled with it long before they became Fairy Godparents. From the Darkness came the Eliminators, who attacked the fairies in large numbers. Only when the fairies combined their powers to neutralize the Darkness by using its natural enemy, light, did they manage to stop the Darkness completely. The Fairy Council sent the most powerful fairies into the void of space to keep the Darkness in check should it ever return, and these fairies took the appearance of stars in the sky. The fairies then left behind a three powerful wands that could only be wielded by a Chosen One, and etched this prophecy on the walls of a cave in Fairy World.
Thousands of years later, the Darkness returned, seeking out the Chosen One prophesied to stop it. The ancient fairies in the stars were unable to halt it, and the Big Dipper disappeared when all the fairies in that sector were consumed by the Darkness, while sending out Eliminators to seek out and capture whoever the Chosen One was.
In its most commonly seen form, the Darkness resembles a swirling vortex of red, black, and gray clouds. The Darkness is very large on a celestial scale, and is capable of consuming an entire planet. Weapons and even magic seem ineffective against the Darkness. Inside of itself, the Darkness is capable of creating a fake Dimmsdale paradise for Timmy and is immortal. After the Darkness's true intentions are revealed to everyone and it is purified, it takes the form of a smiley sun, and remains this way for the rest of its appearance. The Darkness has not been seen since Wishology.
The Head Eliminator, later known as The Destructinator, wants to destroy Timmy Turner, that much is apparent throughout the series. However, Timmy Turner was the only one whoever blasted anything nice and non-threatening into the void, thus endearing the Chosen One as the ONLY one. Its goals change from self-defense to self gain, and the Darkness demands to its servants, in no uncertain terms, to bring Timmy to it.
On the Blue Moon in the Vegan system, after the Darkness creepily moans his name, Timmy realizes the only option to protect his friends and family from the Eliminators' assault is to give himself up to the void, much to his friends/family/god family's/worst enemies' despair.
Timmy is knocked out in The Darkness and is carefully folded close to the Darkness' heart. Once Timmy awakens, the Darkness has the puzzled ten year old live a terrible day - and then a perfect existence. Timmy is about to kiss Trixie Tang...when a group of Eliminators interrupt.
It is revealed that the "Eliminators" are actually Cosmo, Wanda, Poof, and Jorgen in disguise, to rescue Timmy. After a high speed chase and pursuit, the five manage to escape out of a portal, much to the Darkness' dismay. It now wants Timmy back, but the head Eliminator is frustrated with his master for showing such soft-hearted antics and threatens to kill Timmy himself after blasting the Darkness with rockets.
The Darkness lets out a terrible scream-and then releases its full fury on the Eliminator, sending the pieces of his body scattering to Earth. It then orders the Eliminators that Timmy is to be brought back to it UNHARMED. Eliminator One tips off the Darkness that Timmy was in Fairy World briefly and was heading towards Earth. Encouraged, the Darkness sets off in pursuit.
After the Destructinator was "destroyed", it seems the Darkness still wants Timmy. His friends urge him to use the final wand to rid the universe of The Darkness, but, much to their shock, Timmy refuses. He realized that the Fairies and Wonder World panicked and attacked The Darkness first because they thought it was evil. Instead, he has the Fairies poof up ice wands on all the planets in the Solar System. He then unites all the wands, moving the planets, Blue Moon and Fairy World in the form of a "Magic Celestial Smile", which shone its magic into the Darkness, transforming it into the beaming sunshine that is the Kindness. Soon enough, it sends a "Hugginator" to Earth, with a new catchphrase: "Must....hug.....Timmy Turner!" before returning all of Timmy's allies.
When everyone decides to celebrate, the Kindness looms over Fairy World, shining its light over the KISS concert.