Kulta the Skull Grinder is the new antagonist in the BIONICLE 2015 storyline and one of the villains in the BIONICLE series. He was also the leader of the undead monsters, Skull Creatures . He makes his appearance in the rest of the story, following the defeat of the Lord of the Skull Spiders in the hands of the Toa Masters. Later, it was revealed that he and his army are working for the Makuta of Okoto.
It was later revealed that he was also formerly the leader of the Skull Raiders.
Not much about the past of Kulta but it was said that he was known to be the leader of the Skull Raiders
Kulta was said to be the most terrifying and menacing being, even surpassing the Lord of the Skull Spiders itself.