It is the mark of Angra Mainyu. There is another here who bears it as well, but she and I are not from the same version of our world. It is hard to explain exactly what it is, but it and the rest of my appearance is an outward indication of the slow corruption of my soul from what I once was.

I have been touched by all the evils of the world, but instead of being consumed by them as most would, I was strong enough to withstand them, but not without being marked by it.