Well, it looks at least pretty close to balanced. I like the Spirit of Contempt ability, though it does seem slightly broken when used by a Dragonborn with the right Gear.
The Hostile Mercy power is the kind of unique or odd power that can be broken too, with the right gear. There is a Waist item that gives a high resist to all damage while the wearer it at 0HP or fewer, for example. But it will not happen until level 22 and is a small area, so it is in the balance threshold of the Epic tier so I think it might work out.
"Sow Strife" Is a very effective daily, the kind that can Screw up a whole fight, if used at the right time. Any creature with Threatening Reach is Efed up by this SO MUCH it wouldn't be funny.
GF