Archatron

(I can't find a definition for this word. Cormac McCarthy uses it on page 282 of Cities of the Plain in the following sentence:

She leaned and kissed him and stepped away and then the archatron came forward with his sword and raised it in his two hands above him and clove the traveler's head from his body.

Here, the "archatron" is the leader in a ceremony of ritual sacrifice.)