As far as I can tell, the bend occurs over half the wheel. It is tacoed, not radial. Radially it appears true. I have 32 spokes, so the best way I can describe it is this way: The rim that corresponds to spokes 1-16 is true. The rim from spokes 17 through 24 goes from 0mm to 5-7mm out of true, and then over the course of spokes 25-32 returns back to 0mm/true. It doesn't look like a sudden bend, in fact I can barely see it from most views when I look across the rim braking surface held flat. The rim is an 18mm inner width Alex 26in mountain rim. Forget exactly which one.
The bigger question: Once I loosen the spokes, how should I go about straightening the rim? I have no prior experience and don't want to wreck the rim.