[SurlySeraph]

Cool. Basically an undead that's really hard to hit (miss chance and pretty good armor class), hard for the cleric to kill (turn resistance, positive energy resistance), and still well-balanced. Maybe you should make it immune to fire and/ or cold, if that wouldn't increase the CR too much. On the other hand, this looks like you'd need spells to really handle it because it's hard to hit or turn, so that might make it too powerful.