Xerxes tells Vishap that they need his head for the king - and that he'll be revived without the sorcerer's curse if he allows him to take his head. Vishap trusts them, and in page 100, true to Xerxes' word, his head returns to his body in a plume of smoke.
Osric narrates Xerxes talking to Vishap - Panel 3 he is signing 'magic', and panel 4 'decapitate'.
Ace of Beasts has a mythological feel to it :3c