Troll Cross is an unlockable Book of Fables entry in The Wolf Among Us, earned during the course of "Smoke & Mirrors".
Book of Fables Entry[]
A troll cross is an amulet made out of iron that was thought to protect the wearer from trolls. Lily acquired hers while wandering through the wilderness searching for something to eat. She came across a human, but before she could devour him he held the cross out and shouted, "Back! Back you troll!" After enjoying her tasty snack, Lily plucked the cross from the dead man's hands. After the Exodus, she wore the troll cross constantly as a reminder of better days.