Nelson Kasper Van Alden (alias George Mueller) is a fictional character on the HBO television series Boardwalk Empire, portrayed by Michael Shannon.
In the midst of trying to tackle one of Prohibition's most notorious bootleggers, Van Alden's volatile temper and self-loathing start to blur his ethics and by the end of Season 1 he has killed his corrupt partner Agent Eric Sebso (Erik Wiener) and violated his religious values through a one-night stand with Nucky Thompson's ex-mistress (whom he accidentally impregnates).
Nelson finally snaps and uses an iron to burn the face of one of his tormentors; months later, when the man and his friends jump Van Alden in an alley to get revenge, he pulls a gun and kills all three of them.
By the end of Season 3, Van Alden resorts to hiring himself out as an enforcer for Dean O'Banion (Arron Shiver) and eventually Al Capone (Stephen Graham), still going by the name George Mueller to avoid the authorities.
With Van Alden's deteriorating home life and facing death at the hands of the Capones, he snaps and attacks the brothers while Eli and Malone watch in shock.