Well Grindor here is fresh out the battle with Optimus and has plenty of scars to show just how powerful the Autobot leader is, even when it's 2 on 1. Grindor has suffered a major blaster hit in the midsection from Optimus while trying to distract him for lord Megatron's flanking move. This didn't work out so well as lord Megatron took a foot right in the face, less painful then what Grindor got! Grindor recovered himself and pressed forward to aid his Lord Megatron only to recieve another blaster hit in the upper right side but luckily Grindor was quick enough to avoid the blast somewhat and only recieve a singe on his side. But Optimus was determined to stop Grindor in his tracks firing again, to which Grindor jumped over only recieving minor burns on his knees and legs. Just as Grindor hit the ground only a few feet from striking distance to Optimus, Optimus bore down his blaster at point blank range and blasted Grindor directly in the chest sending him 20 feet backward sliding on his back. By this time Grindor had had enough and retreated quickly followed by his Lord Megatron who took a few scars home as well. Though the next encounter would take place in the forrest and be the end of Optimus, it will also be the end of Grindor.
Grindor has been scorched with a lighter in different places to simulate the blast/melted metal look, airbrushed with dark grey and silver shades for a dirty metal affect and given black and gunmetal shading for the extra weathered/scorching look.
I'd say after the battle Grindor just went through he definitely fit's into this theme and common give the guy a break, his next fight takes place in the forrest where he gets his face split (sshhh) don't tell Grindor, he still feels lucky he made it out from the last encounter with Optimus and thinks he'll be safe at Lord Megatron's plot to include Starscream next time, 3 on 1 is a sure thing Lord Megatron says.