This is the second time I lost one overpowered Berserker build to crit attackers in mass, in Maze (level 11). I guess I need a better thinking on this.
My thinking would be to not let crit attackers (or any attackers) attack you in mass.
I walked down a stair, and faced with 5 thief in one case.
In one case, a mini boss thief summoned a crit familiar, with which they got me with one shot.
Generally I am also aware of not walking through hordes, but being a melee fighter, luck can have devastating results.
I do have to admit, at least half my deaths are from getting suddenly multi critted for about 4-5x as much as I'm used to taking in a given area.
That said, I seem to recall that improving the armor mastery decreases either the chance of being critted, or the amount of damage they do on crits. Dex does something similar.
I lost a Staff Shadowblade having died all 7x (not Roguelike) fighting Argoniel and the other dude.
Got critted by a Freeze from that other dude, despite me having a Heroism infusion (-800+) while at 600+ HP.