Arceus is a majestic being, perfect for coloring. I would color Arceus' face and mane with a soft white, while the tips of its tail and wings could include a lighter shade of pink, like a pastel. I would use a deep pink for the jeweled mask, and a light pink for the jeweled bracelets. The horns could be a white with a touch of pink at the base. The black blaze and tuft should be colored with a deep, rich black. To complete the look of Arceus, I would color its eyes with a mysterious navy blue.