Jaki

Jaki, literally "evil air/breath/atomosphere", is the manifestation of negative emotions.

Typically it is harmless. In fact, its existence is necessary for the balance of emotions of the world. However, in high concentrations it can be used for malicious purposes.

Diadora, for example, absorbes jaki into her womb, and gives birth to Duendies, malevolent beings made of pure jaki. The Duendy also absorbs jaki to make themselves more powerful.

The high concentrations of jaki leaking out from the Crystal Palace, slowly overtime corruptes people into In.