And the bodies of trolls are shot through with copper.
In most cases, this copper manifests as plates or knobs on the troll's shoulders and neck, and curved plating over their forearms. Let's take a peek at the art of a few Mirrodin cards to see the trolls' coppery demeanor up close. Included are small windows of the initial sketches of the troll art so you can get a little before-and-after action.
Trolls of Tel-Jilad by Marcelo Vignali
Tel-Jilad Exile by Justin Sweet
The copper on Troll Ascetic is a little more subtle, since he wears furs that cover his back. But you can see copper over his claws, a bit shining on his neck, and a couple of knobs on his left shoulder.
Troll Ascetic by Puddnhead