For this method you will need 2 controllers.
Go into Battle, then select Versus. Change the settings to player vs player, 5 rounds, and infinite time. This will give you plenty of tries with minimal loading.
Select Astaroth with your profile. the other character doesn't matter.
Once the round starts, hit
with your controller, then mash
on both controllers. The first clash will end in a draw, but the second clash will result in the "Rending Torment" move.
Repeat 3 times and the achievement will unlock.
Edit: Reverend M3TA suggests not quitting out due to the glitchy "Get All Achievements" Achievement. So instead of quitting out, complete the match.