Those Slann really turned out nicely. I especially like the effect you achieved on the eyes. They appear wet and "froggy" if you know what I mean

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Did you consider alterating the colour in your regiments, so have some green, some blue, some red Slann? I could also see some cool markings like spots or stripes, but I am not sure if this suits the fluff.
Overall a very nice paintjob in this small scale. Do I understand right that the idea of Oldhammer is to use any older sculpts to depict Warhammer armies and play using older Warhammer editions?