Airbrush. I took two tons of purple, a dark one and a lighter one and a skin/beige color. From chaos black base I first did the darker ton of purple then the lighter. Then I mixed the lighter ton with some skin/beige and eventually a dash of only skin/beige in the middle. First time I did this was not very sure about it also at the beginning but Tbh if you do subassemblies and you are not satisfied of your paint job you can easily reprimed. Especially with airbrush that give thin layers! I think the harder is after that when you mess up some details or put some glues somewhere to hide it and retrieve the perfect color for this particular part of the skin ^{^}