Avenger North is the creation of Samantha Flynn (Booksbooks3). You can read more about him here and here.
Avenger North is the leader of the Cyran Avengers. He was previously the head of the Cyran Espionage, under the name Glove Spectre, a role he was promoted to from the Black Gloves nearly a decade before The Mourning. He was married to Whisper Flame.