So, we all know the shtick (at least if you've gotten to that point in Mirage), Xerxes shows up in the ossuary and you're like 'wow, only 5000 health?' and then he steals the life from all his minions, and he's got 15000. But, there is a glitch I found, where if you flee and come back, his minions will not be there, and he will only have 5000 of his max 15000 health.
This makes the fight much easier, and me, as an ice wizard, which have the objectively weakest spells, was able to beat him in an astounding 5 rounds.