I like how there's a human for scale, as if the fact that it's litterally made of human skeletons wasn't enough.
Someone on the internet once said that this should have an ability that makes any creature in its space get grappled by all the skeleton that compose it, and eventually get absorbed in the Charnel Hound. That would have made it a pretty interesting monster, instead of the HD-bloated melee thumbless undead it is.
As it is, the charnel hound is mostly a Huge beatstick with enormous strength (+28 Str), pretty good HP (+8 Cha and Unholy Toughness), the regular claw-claw-bite and a +16 natural armor that will be pretty good with a lower amount of HD. Apart from it, it has a few moderately useful abilities, like DR 10/Silver and Magic (I'm sure the Magic part will be useful at these levels), Rend and Power Attack as a bonus feat; a few barely useful abilities, like SR 2+HD, Frightful Presence and the ability to heal itself each time it kills a humanoid (that would be extremely good if it was any creature); and a few outright detrimental abilities (lack of thumbs, -8 Int, and aversion to daylight which gives it -4 to most rolls under the sun). So, what is something that strong, but with half-BAB, no hands, and the least amount of versatility I've seen in a long time, worth? It's definitely worse than a Cloud Giant, with worse overall stats, BAB, and body shape, but the undead immunities with Unholy Toughness make it better than a Fire Giant in my opinion. I'll say 9 RHD is good here.
Next time, after the horrific over-RHD'd dog with no good ability, we'll have the horrific over-RHD'd spider with no good ability! See you then for the chelicera!