Digital painting in Ruan_Jia style, extremely refined surface quality, atmospheric lighting, luminous skin, soft controlled brushwork, subtle color harmony, rich depth, painterly masterpiece illustration, Cthulhu emerging from dark turbulent ocean waves in a colossal towering pose, enormous tentacles writhing and reaching upward, ancient winged body partially visible above the water, glowing eyes staring directly forward, massive ancient city ruins on distant islands in the background, ominous low-angle view capturing overwhelming scale.