Yah (pronounced "y-ah-kh") is a mortal soul of a living being.
It contains the memories, subconscious and even genetic information about a being. Similar to the concept of mind in some of Earth's cultures.
Yah can be damaged, altered and destroyed. Famous examples include Viroka's death in and by the city of Rumas, Kettohi's madness after her Yah had been warped during her training by Nax, whose Yah was partially corrupted leading to her falling into vegetative state.