You will need to collect all 200/200 gold bricks to unlock Voldemort then purchase him from Madam Malkin’s Robes.
Then load up year 1 level 6 Face of the Enemy selecting Voldemort
as your main character.
Now play to the end of the level to attack Quirrell and remove his 3 hearts.
I personally had an issue removing the first 2 hearts with Voldemort so I used with Harry to remove the first 2 hearts, then on your final attack change to Voldemort and attack with
, however, this may not be an issue for others I just wanted explain how I did it if others have the same problem.
As soon as the cinematic comes up the magic sound of the pop achievement unlocked.