Kali is the demigoddess daughter of the goddess Sacrier and a member of The Siblings.
Her history with The Siblings or her relationship with the other members is currently unknown. She appears very late in Season 3, her personality and her Sacrier room are never explored.
She is however fully explored in the game, when the player reaches the middle portion of Mount Zinit and her dungeon, Kali's Lair, filled with Sacrier acolytes and Kali herself as the final boss. As an NPC, she shows to be quite sadistic, snarky and shows quite an amount of sass to the player, but nevertheless seems to be on the player's side to help him/her reach the top of Mount Zinit.