Tha Nai is the first man of Karen tradition, formed by Y'wa and set with his wife Ee-u in a state of innocence under a single prohibition. Deceived by Mu Kaw li into eating the fruit of trial, the couple forfeited that innocence, and through them sickness, ageing and death passed to all their descendants. The pair function as the Karen Adam and Eve, and the episode is the hinge of the tradition's account of why humans die. The exact form of the names is unstable in the record: the nineteenth-century collectors transcribed the first parents variously, so that Tha Nai and Ee-u appear in several spellings.