Trusty John

Trusty John is a Fable who is known for being trustworthy. He is unable to break a vow unless it conflicts with a previous one that was made. Currently, he lives in Haven.

Homelands
In the homelands, Trusty John made a vow of unbreakable fealty to his king. After his king died battling the Adversary, John left his home and came to Fabletown.

Fabletown
When he arrived in Fabletown, he became one of the guards for the apartment building. Later, he was contacted by his king who he had thought to be dead. The king commanded him to spy for the Adversary and John was forced to obey. Kay found out about it and reported him to the authorities. John chose to jump down the Witching Well alive.

When Ambrose went down the Witching Well, John was one of the Fables that decided to follow him.

Haven
Upon reaching the new kingdom of Haven, John quickly became one of Ambrose's most trusted advisors. He allowed the soldiers of the Adversary to attack him to demonstrate Ambrose's powers before the first battle of Haven.

Following the final battle of Haven, Trusty John was put in charge of most affairs of state.

Source
The character of Trusty John is based on the Grimm fairytale of the same name.

According to the story, a king sees a portrait of a princess and falls in love with her. He prepares a ship full of treasure and sends his servant John to get her. He manages to get the princess to come with him.

On the way back, John hears three ravens. The first says that when they reach shore, a horse will come. If the king gets on the horse, he will be killed. Anyone who says anything about it will be turned to stone up to the knees. The second says that the king will be killed by wine at the wedding feast if it was not dashed to the ground. Anyone who says anything about it will be turned to stone to the waist. The last raven says the princess would die unless someone draws three drops of blood before the king touches her. Anyone who says anything about it will turn completely to stone.

John is able to prevent all three fates. For the first two, the king forgives him. For the last, he decides to execute John. John explains the story and turns to stone instead. When the queen gives birth to twins, they are killed and their blood is rubbed on John. John is turned back to flesh and both twins are brought back to life.