Kalku or Calcu, in Mapuche mythology, is a sorcerer or witch who works with black magic and negative powers or forces.
The essentially benevolent shamans are more often referred to as machi, to avoid confusion with the malevolent kalku.
The word kalku is a borrowing from Puquina language[1] Its adoption by Mapuches fits into a pattern of parallels in the Mapuche and Central Andean cosmology (Inca religion) dating back to the times of Tiwanaku Empire when Puquina was an important language.
[1][2] The kalku is a semi-mythical character that has the power of working with wekufe "spirits or wicked creatures".
Kalku is the main antagonist of 2020 Annecy nominated Chilean-Brazilian featured animated film Nahuel and the Magic Book created by Carburadores and German Acuna.