Lycanthrope

Lycanthropes (from the Greek λυκάνθρωπος: λύκος, lukos, "wolf", and άνθρωπος, anthrōpos, man) were humans that were cursed and had the ability to shape-shift into wolf-like creatures. The first of the Lycanthropes was Lycaon.

History
During the Ancient Times, Zeus decided to dine with Lycoan, King of Arcadia. To prove that Zeus really was who he said he was, Lycoan tried to feed him human flesh. Zeus became so enraged he slew Lycoan's sons with lightning bolts(except maybe for one) and made Lycoan into the first Lycanthrope.

The Lost Hero
Seen in The Lost Hero, Lycaon and his Lycanthrope minions awaited Jason Grace, Piper McLean, Leo Valdez, and Coach Hedge when they were one the search for Aeolus. He ordered his minions to kidnap Jason, and kill Leo and Piper. They were later defeated when the Hunters of Artemis arrived. Lycaon was the only one to escape.

Weakness
The Lycanthropes are immune to gold, bronze, steel and iron. The only thing that can kill them is silver. They can also be hurt by fire but not fatally.

Known Lycanthropes

 * Lycaon