I take the form of a gray-bearded street magician.
"Consider now the heart of illusion, which is the manipulation of darkness and light to create visions and cause effects without the need for 'reality'. Even the minds of the greatest deities can be fooled by well-formed and well-planned illusory effects, for masters - such as I - can weave light and darkness so well that reality itself will be unsure of its composition.
"Consider also the heart of poison, which flows through my veins in the form of Quicksilver and Adamant. If my lungs can breathe madness, my heart can beat death, and my muscles overcome paralysis, are you to believe that there is much that I cannot do with poisons and toxins? Stand ye still, otherworldly creature. Feel free to watch our show; but we would like to know who stands in our audience."
I work a debilitating neurotoxin of mind-slowing, paralyzing light through Durin's lantern and through my own illusions, hoping to slow the shadow-creature still further and weaken it to our observations. It will be integrated directly with the light and dark, so that the creature cannot feed without also consuming poison.