nice stuff, like your purple guard and the blue giant, fits very well IMO.
coincidence, i just finished painting a batch of ogres for a friend of mine and i came up with quite a similar blue skin tone… used astronomican grey and asurmen blue (with a touch of badab black) for mine, how did you do yours?
Unusual to see purple Chaos Dwarfs. I think they look good, especially the Daemonsmith. The skin on the Siege Giant is great. Will you paint emblems or runes on the Infernal Guards’ shields? I think a painted lightning bolt on one or two armour parts would help tie in your Giant with the CDs.
Good shield marking. As ChungEssence already have said, it matches the purple, and also seem quite simple to pull off for a good effect. Will you mix the emblems? Then you could include a skull with a lightning bolt in its forehead, or a volcano spitting lightning, or a bull’s head, or a Chaos star on some shields. That really isn’t necessary, but might give you some challenging variation in the shield painting.
Anyway I think you should paint the rune of the shield on some parts of the giant’s armour, too. It doesn’t need to be large.