Plus the Yellows contrasting with the black armor really pops well on these models. Checkout the summary and pics below.
From Next Level Painting;
This highly customized pre-Heresy army showcases many original models from the Forge World line. All the space marine infantry sport Mark IV Maximus Armor with it's distinctive helmet that's particularly fitting for this Scorpion themed force. The Rhinos are made from a unique combination of the Deimos Pattern and Repressor kits from Forge World as well.
Be sure to click through the Gallery here to see close up pics of all these models.