As a young man, Ambrose was cursed by Frau Totenkinder to become a frog until a kiss from a princess freed him from his amphibious form. However, the cure was not permanent. Whenever Ambrose became overly excited or nervous, he would revert to frog form again. However, having married the princess, this did not present much of a problem. They had a family and he was about to marry off his oldest daughter when his kingdom was attacked by the forces of The Adversary.

As they broke into the tower, the frightened Ambrose reverted to frog form and was forced to watch as the Goblin raped his wife and daughter and slew them and his entire family. Since he was just a small frog, the forces did not take notice of him. It is believed that he stole a final kiss from the lips of his dying wife which reverted him to his true form. But the emotional trauma of what he had witness was so great that he forgot what had happened and began wandering the Fablelands searching for his family. Only if he got very drunk did he seem to realize what had happened.

Eventually he crossed over into the Mundane world where the Fables did their best to keep the deaths of his family from him. Constantly breaking the Fable laws of trying to keep the “Mundanes” from realizing their true nature, Ambrose was constantly working off community service hours garnered by eating flies by acting as custodian of the Fable Town City Hall. He even slept in the basement of the building. At one point, after Bigby Wolf left, the Beast attempted to “free” Ambrose by waiving his community service since his infractions of eating flies was so minor an offense. Rose Red explained to him that Bigby had kept busting Ambrose since without his job, he was completely at a loss and would feel honor bound to return to the Fablelands to search for his family. Beast put Ambrose back to work.

Ambrose has been a supporting player until very recently. When Ambrose suddenly realized he was attracted to Red Riding Hood, the shock of it turned him back into a frog. For the first time since his wife died. In this form, he regained the memory of what had happened to his family. Santa Claus brought the ghost of his wife back to return him to his human form and told him that he was going to serve a great purpose in the coming war between the Fables and the Adversary.

After morning for a time, Ambrose decided to return to the Fablelands to exact revenge on the Adversary, He asked his best friend Boy Blue for help. Boy Blue refused, revealing that of every Fable that had come to the Mundane World Ambrose was the only true innocent. Disheartened, Ambrose returned to City Hall. That night he was awoken by the voice of the Forsworn Knight, who was revealed to be ghost of Lancelot du Lac who stated that his penance for betraying his Arthur and Camelot was to assist Ambrose on a quest to retake the Homelands from the Adversary. He cleaned Ambrose in the full ritual of Knighthood, gave him his enchanted amour and bade Ambrose to pull Excalibur from the stone. Ambrose succeeded, proving that he was worthy to be king, though king of what is unknown. Ambrose and Lance are returning to the Homelands through the Witching Well in the back rooms of City Hall.

As Ambrose's trip through the Witching Well brought him closer to all of the "Dead" Fables, it was here that he started building his army in the hopes of creating a newfound land for all the Fables that have taken residence in the gloom of the well. His army includes almost all of the deceased Fables, including established villains such as Bluebeard and Shere Khan, both of which will betray him to their own greed and avarice as the plot unravels.

Flycatcher has just recently been involved in building the new Kingdom of Haven, a newly crafted Homeland smack in the middle of The Adversary's empire. It is here where he taunts The Adversary by spreading hope for a new life among all the trapped ones of the various homelands that have been conquered. Now known as King Ambrose, he has lead his army to successful battles against the hordes of the Empire, dispatching each opponent without spilling blood on either side as was his first objective. He accomplished this by virtue of a nullification of any magic in his kingdom other than his as well as by making full use of the power of an army filled entirely of ghosts. The ghosts were impossible to kill and with no magic to aid them, the mortal forces of the Adversary were quickly routed.

The defeated members of the hordes were allowed to join his army and with each passing battle, the martial strength of Haven grew to the point that The Adversary could no longer ignore him as a threat.

The last battle that Ambrose and his fledgling Kingdom were involved in was against the Golden Horde; an army composed entirely of elite wooden soldiers from Gepetto's Sacred Grove, all carrying magical weapons. Ambrose planned to sacrifice himself by letting his magic transform the soldiers back into trees and thus, into a new Sacred Grove. The plan originally required his death but by some stroke of luck, he survived and is now in possession of The Adversary's most powerful weapon.

The last thing that Ambrose sees after the battle is an image of an army of Wooden Soldiers, all under his command, wreaking death across battlefields with him at the helm, supposedly repeating the horrors that The Adversary had done centuries ago. Whether this is another one of his premonitions or just a fear that he keeps has yet to be seen.