LEGO Harry Potter Years 5-7

You need to unlock and purchase these character for the Dark Times Ahead achievement:

Lucius Malfoy
Snatcher
Scabior
Yaxley
Tom Riddle
Antonin Dolohov
Bellatrix Lestrange
Bellatrix (Azkaban)
Lord Voldemort
Thorfinn Rowle
Grindelwald (Young)
Grindelwald (Old)
Mrs Black
Dolohov (workman)
Pius Thicknesse
Wormtail
Alecto Carrow
Amycus Carrow
Fenrir Greyback

Just a tip: These characters--Lucius Malfoy, Snatcher, Scabior, Yaxley--are all found in the forest area with the tent (along with a gold brick). You'll need a dark wizard to get them. The portal pad to the forest is located by the diner in the city/muggle area. It will transport you into the tent. There is 1 dark magic/character in the tent; the rest are outside it in the forest.

for locations of characters here are some videos to help you i did not make these videos all credit goes to EscherMedia the video poster they are set in zones making it easyer to follow