The 13 Masters of Evil
Fathrhanna was an elven ranger, and part of the Yellowtail rangers. The party met her in Yellowtail while looking for information about Lorleek and the missing villagers. She had made a map for Lady Arerein of features around Yellowtail, including the site of the dig for which the villagers had been hired.
The party later came upon her while investigating the portal leading from the Ruins of Cilox to the Yellowtail cemetery. She was accompanied by undead creatures, and so the party attacked her. She was found to have magic symbols of the Dark Son cult on her. This combined with the fact that the password to access the cult’s stronghold had to be spoken by an elf showed that Fathrhanna was the traitor as whom the party posed to access the stronghold. The party later used the symbols carried by Fathrhanna to bypass the fire trap on the stairs leading to the Dark Son cult’s inner sanctum within the Ruins of Cilox.