I ran the Infernal Dungeon Achievement.
Tried different variations with all 3 required toons but was unstable. Looks like 600 total runs may be required.
So far: Avg. Time 2 to 2 1/2 mins.
Gambler- warlord/radiant
Eternity Ed (in back pocket)
Set-labrynth/cosmic
Beast-mark/sustain/cosmic
Musashi-alchemy/cosmic
Tried it with Wrath instead of Musashi, even used Angel talis on Wrath & Beast, but those marks takeout Set.
That 1st wave with the S. Trolls have critical strike.