Dark Kaia was an evil version of dreamwalker Kaia Nieves who was a human who possessed the ability to view alternate universes. She appeared in Supernatural season 13 and was a recurring antagonist in the season ans a anti-hero in Season 14.
However, whereas other dreamwalkers could roam freely between worlds at will, she was trapped in "The Bad Place" every night where she was scratched, stabbed and beaten by a Hooded Figure. This Hooded Figure was the Bad Kaia, who appeared as a sinister individual in a dark leather cloak. She was much more primitive and barbaric than the real Kaia.
Kaia was understandably much afraid of the evil figure, and vowed never to return to the Bad Place. She told Sam and Dean of the place and she freaked when Dean wished to lead her back there to use her dreamwalking ability to free their tortured mother, Mary, who was in the grip of the Archangel Michael. Using Jack the Nephilim, son of Lucifer, they managed to convince Kaia to take them to another universe. However, Jack accidentally put them all in the Bad Place, also known as "Dinosaur Universe."
Escaping from monsters, Sam and Dean met Dark Kaia, who tortured them. She even went as far as to kill Kaia with her spear. But as Sam and Dean returned to Earth after much hassle, the portal was still active, and as Claire Novak recounted how she and her team saved the Winchesters, Evil Kaia jumped through and smirked as she had rejoiced in finally coming to Earth.