What Were The Immortals Depicted In Frank Miller's "The 300" Really Like?

The immortals were an elite fighting force that existed at the time of the Achaemenid Empire in Persia. No record of their actual name is found in Iranian literature. Their name actually comes from Greek records. They were the elite units used by the Persian Kings as imperial bodyguards. They numbered ten thousand in all and any loss of troops was immediately replaced. They did not wear any face mask as shown in the film and were not deformed in any way.

Though they wielded all types of weapons including swords they were believed to be particularly good with arrows and with spears unlike the two swords they wielded in the film. They were thought top ride and were educated in religion as well. In the Battle of Thermopylae it was they who finally encircled the Greeks and annihilated them.