The Dark Side of Kinkow was the opposite of the Light side and the place where the vast majority of trouble for the island happens. It is mostly shrouded in mystery. The Dark Side was eliminated with the final defeat of Kaita.
While the Dark Side is not as big in terms of size in comparison to the light side, the Dark side seems to hold a large amount of secrets that few know about. It was created by Kalakai and brought to life by Zadoc. (The Evil King, Kings of Legend))
The waters around the Dark Side have a dense mist that covers the water and holds it dangers. (Wet Hot Kinkowan Summer)
Unlike the Light side, the Dark Side has a far more variety of creatures and monsters.
- Tarantula People: The most recurring of the Dark Side creatures, the Tarantula People are the only known human population on the Dark Side. While some Tarantula People can speak English others speak in their own language known simply as Tarantula. Their leader is the Mummy, but they also have Shaman and some sort of system.
- Gil & Gilda: Two toad-like beings that serve an overload out of fear, they lead people into traps where they feed them to the giant toad they serve.
- Giant Toad: The Dark overlord that Gil and Gilda serve out of fear. It was bested by Mikayla.
- Waka Waka Bug: A large mosquito-like creature that inhabits the Dark Side, stinging it's enemies and giving them Waka Fever and sometimes Muku Fever. It is only attracted by coconut sunblock and cheese.
- Kinkowian Bogsloth: A humanoid species that is attracted to stinky things. Brady and Boomer tamed one as a pet named Mr. Boogey.
- Giant Spider: A large spider creature that inhabits the Dark Side, it's only weapon being it's fatal bite that can crush a human being. It was defeated by Brady and Boomer when they used special lightning bugs to attract lightning to it.
- Mummy: The king's main enemy, whom the Tarantula people serve. It wants to take Kinkow away from the kings. He was defeated by a king in battle, and needs a king's spit to bring him to full power. The Bat Medallion brought it to life, meaning power of action and brain power and volition.
After an intense argument between the first twin kings Kalakai and Malakai, after Kalakai was stopped by a sasquatch ancestor of the Makoola family he fled to the unexplored part of the island and started the Dark Side. (The Evil King)
- In Kings of Legend it was said that Zadoc brought the dark side to life. It was presumed that it meant that Zadoc created the Dark Side, however later in The Evil King it was revealed that King Kalakai created the Darks side. It is more likely that "brought the Dark Side to life" meant that Zadoc increased the power of the Dark Side.