- "Their parents said they were ordinary triplets, but I thought otherwise. They were a nest of Doppelgangers, and had to be burned. As the fire took them, the smoke twisted into unholy sigils, and I felt relief to be so vindicated. On later reflection I realised that, if I felt relief, it was because I had felt doubt. This is the strength of the Doppelganger, to spread doubt among even the most faithful. I resolved never to doubt again."
- —Abelhelm Mueller, Witch Hunter[1a]
Doppelgangers take on the forms of others, then kill and eat those whose appearance they have stolen, replacing them completely. The brain is said to be their favorite morsel. Doppelgangers infiltrate positions they can use to further their dark and inscrutable agendas, and prefer to take the forms of the highest members of society.[1a]
In their natural shape, Doppelgangers look like walking anatomy diagrams: skinless humanoids with muscle and organs plainly visible. They are rarely seen in this shape except in death, however, as they may take the appearance of anyone they have seen, even down to clothes and armour. Not only that, they are able to ape the mannerisms and personality of their targets so well that even family would have difficulty telling them apart.[1b]