Betrayed by Fulgrim, the errant House Vyridion shed their previous sea green livery in favour for the purer black and gold of imperial majesty. No gaudy sigils of self aggrandisement, the House instead wore the Imperial Aquila, reaffirming fidelity to the Master of Mankind.
This is a much bigger kit than you may initially think. It's a mini knight Titan (the guns are bigger than a plastic dreadnought). Making large surface areas like this interesting is challenging, especially the gold plates, but with overlapping contrasting colours you can achieve a depth of interest that you typically wouldn't be able to achieve using a brown wash.
The knight's paint scheme was inspired by Master of Mankind House Vyridion. The simple black and gold marks with Imperial Aquila's was made so much easier using the Custodes transfer sheet.
Paint Black like this by taking the Black armour painting course: