The Branding Iron artifact can be found at Uruk's Hollow, in the central-eastern part of Udûn.
Branding Iron, Orcish, Third Age, 2942
"Not Old Scorchy!" is a common refrain among the Orcs of Udûn. It is interesting to note that while branding with red-hot irons as punishment is commonplace, with the Orcs searing the flesh of their unruly brethren as much as they do their slaves, Old Scorchy is unique, used only on the most recalcitrant.
The Orcs believe Scorchy holds sorcerous powers enabling it to burn longer and hotter, and to scorch with such intensity the pain can be felt for weeks after the branding."
"All right, you. You're not so brave now, are you? Hold 'em, boys.
Get your filthy hands off me!
It's simple, see? Do unto others quicker and harder than they'd do unto you. But at least you tried. Next time, try harder. This is going to hurt. A lot. But you'll learn who's in charge.
No! Not… not Old Scorchy! Anything but Old Scorchy!"