Fen is the son of the Fang the chow-chow and the chow chow high priestess. He has brown and white fur and blue eyes. He is often seen fighting using a sword but also uses a hammer.
Unlike the other children of the villains, Fen's parents were not captured or taken to jail. He instead ran away from home, frightened of his family's cannibalistic nature. He was eventually found by Tayra and her company and taken in by them. He helps them cross the harsh and cold mountains located near Chor Gom prison, using his fur to keep the reptiles warm. When he reaches the Valley of peace, Fen decides to stay with his new friends. He becomes an assistant to Serpent with his performances. Later, he is accepted as a member of The Dragon Knights.
Fen is shown to be a soft, good-natured, and caring boy, being able to overcome his family's evil nature. He is also sympathetic as seen comforting his friends when they're sad or depressed.
Fen and Tayra have a close friendship. When Tayra notices Fen was sad over not having any family to reunite with, she pulls him over to her family and seems to convince her mother and uncle to adopt him.
Fen has a close friendship and possible mutual affection for each other.
Trivia:
Fen is named after the wolf, Fenrir.
He is the only child of a villain whose parents are not in jail.
He's also the only one not to reunite with his family.