I decided to give it another shot. 10586.29, hard reset, NO restored backup.
Device seems stable, everything looks and works good. HOWEVER, it's still killing 20% battery an hour. I was reading Windows Central articles for an hour and went from 97% to 76%. There is NO WAY reading webpages for an hour uses that much power.
I really wish I knew what exactly is happening.
Edit: I am now at 50% after 2 hours of use. I started using the WP Central app to read after the 1st hour to see if Edge was the culprit. Doesn't seem to be the case.
I turned off ALL background apps and power cycled the phone. When I doubled-checked, the HTC Photo Edit app had turned itself back on. I then deleted every HTC branded app on my phone. At 9:50 am I had 50% battery. I will check back in an hour from then.