The Hanged Man is the twelfth of the 22 major Arcana in a tarot deck. He first appears in Julian's route, during chapter 2 of Book XII - The Hanged Man. However, he is not interacted with until Book XIII - Death, also in Julian's route.
The Hanged Man appears as a humanoid raven with brown eyes lined with red. He is clothed in very little, wearing only a grey wrap, or loincloth, and red rope across his chest and biceps. The ropes are done in a shibari style. His wings are draped behind him, as if they were a cape instead of actual wings.
The form he takes, the raven-headed Hanged Man, is the same as the image on the Hanged Man card of Asra's deck.
Since he is one of the major Arcana, he is an archetype, a form of pure and ancient energy in the human subconscious. His archetype is to be self-sacrificial.
He is very calm, unlike the raven Julian knows in the human world. He also asks many questions, prompting people to make decisions for themselves. However, he does reveal large bits of information, most notably giving Julian the cure to the red plague three years before the events of the game.
The Hanged Man gave Julian the magic mark on his throat as a result of a deal they made. He gave Julian the power to heal in exchange for the memories Julian didn't want.