Wikipedia
Keyumars
Keyumars is the Persian form of the name Gayō Marətan (appearing in medieval Zoroastrian texts as Gayōmard or Gayōmart), the Avestan name of the mythological first human being in the world. The corresponding name in Middle Persian is Kayōmart.
In Ferdowsi's Shahnameh he appears as the first shah of the world. He is also called the pishdād , the first to practice justice, the lawgiver.
The Avestan form means "the living mortal", from gaya "life" and marətan "mortal, human being"; cf. Persian mard "human" .
Keyumars is also a popular first name in contemporary Iran.