Willem is a tall, broad man with shaggy stalks of chestnut hair that dangle over his ears. His youthful face lacks any facial hair. The reddish-brown scruff grows unevenly, so he keeps his face shaven to avoid looking like "a hobo"- according to his sister, Vivienne. Willem's lengthy frame also carries some extra weight. It robs him of small attentions that could be garnered from the ladies, but he's always had more than enough women in his life.

Willem DeCarlisle is the eldest brother of seven sisters. The unfortunate and untimely deaths of both parents forced the young man to adopt the role of pseudo-father at the age of twenty-one. Thankfully, playing third parent for the majority of his teenage years made the shock a little more tolerable. The loss brought the DeCarlisle family closer together in secrecy. It also isolated them in ways they never wished for.