Joining the owlbear, purple worm and displacer beast in the long line of 'magical beast with self-descriptive names' is the gray render, a hunchbacked, gray-skinned humanoid with the strength of a troll.
Their 10 magical beast RHD aren't that bad, though the stats are admittedly on the low side.
More interesting is a render's ability to wield weapons. Look at that picture: they clearly have opposable thumbs. While magical beast HD don't naturally give weapon proficiencies, the martial levels any render will be taking do.
In addition, this means the render's bite attack will remain available, and as a result so will its improved grab and rend.
The final verdict is bordering on the +0 and -0, but in the end I'm forced to go with -0. Improved Grab and Rend are nice, but not incredibly strong with the plethora of better damage dealing-options and ways to avoid grapples at this level.
Next time: the grick, which should prove more interesting.