From pretty much all lore we know about Demon Hunters, from in-game to novels to non-canon RPG books, they are all insane in some way or another (Except maybe Illidan but that's debatable). In the Illidan novel, Vandel is shown to have developed a mild form of schizophrenia, literally believing that there is a Demon inside of him egging him on to betray the illidari. Other characters in the novel are even worse, with one stitching his mouth and eyes together and delighting in the taste of blood.

Early on in the novel, it's shown that most elves seeking to become demon hunters were also already insane before their transformation, with their sleeping quarters echoing with deranged screams and random acts of violence being a common occurrence.

All of that to say, how insane do you imagine your DH to be and how does it present in them?

For my own character I imagine that in order to survive the demons attack on his people he had to remain perfectly silent and hidden and since that day has gone mute due to trauma, and the transformation into a Demon Hunter has made him devoid of any emotion. Looking forward to seeing people's answers or if a DH's insanity is even considered by most people.