Okay I can't for the life of me find the picture that I was thinking of but regardless here is the rough idea I have sorta similar to the goblin but less heroic. So this new character is known as the Wanderer in tales on his world, once a hero who travelled the land helping those in need and fighting monsters but one day after delving into deep into a long forgotten cave he stumbled upon a strange device that when activated trapped him in a dimension called the plane of shadows. He was trapped for so long the energy of the plane began to corrupt him, turning him into a shade. It also made him immortal, but centuries trapped in a plane of infinite darkness drove him somewhat mad and the hero he once was slowly faded to an echo.