Ormus The Penitent.
because:
I was once a paladin, <name>. Now the Light shuns me, for my sins are too great.
I will aid my allies as best I can, but never again will I wield the powers of darkness.
Ormus, what happened to your eyes?
A self-inflicted wound, friend. I could not bear to look upon a world where I'd committed so many horrors under the Lich King's grasp.
It was my first step towards redemption, and if my sins are unforgivable, then I will attempt to atone for them for the rest of my life.
that penance. Sooooo badasss!