Death Eater & Dementor Costumes
Death Eaters are a group of wizards and witches led by Voldemort who seek to purify the Wizarding community by eliminating the Muggle-borns. They spread fear by killing important officialy and other enemies of the the Death Eaters, mainly members of the Order of the Phoenix. They all have a dark mark on their left forearm, a sign created so that Voldemort can summon them at anytime or vise versa.
The Death eaters practice illegal and dangerous spells known as dark magic. The most faithful was Bellatrix Lestrange. She was extremely devoted to Voldemort and takes pleasure in acts of torture and cruelty. If you want to join the ranks of these evil wizards, a Death Eater costume can give you the dark look you're after.