a scifi  illustration  by  tsutomo  nihei  , robot, weapon, mecha, no humans, science fiction, gun, holding weapon, glowing, holding, red eyes.  The image is a digital artwork featuring a highly detailed, futuristic, skeletal robot with a dark, industrial aesthetic. The robot, standing upright, has a skeletal structure made of dark, metallic components with intricate, glowing red eyes and a menacing, skeletal face. Its torso is adorned with mechanical parts, including a glowing, circular panel on its chest and various pipes and cables. The robot's limbs are elongated and articulated, giving it a menacing, humanoid appearance. 

It holds a large, complex weapon in its right hand, which appears to be a futuristic, mechanical gun with various mechanical parts and a glowing barrel. The robot's left arm is bent at the elbow, with a smaller, less detailed weapon attached to its hand.

The background is a dark, gritty, urban environment with tall, crumbling buildings and a smoky, industrial atmosphere, suggesting a post-apocalyptic or dystopian setting. The color palette is predominantly dark, with hues of black, grey, and dark brown, with the occasional splash of glowing red from the robot's eyes and weapon.

The image is divided into two sections: the main, detailed view of the robot in the foreground, and a slightly blurred, more stylized representation of the same robot in the background, emphasizing the overall theme of advanced, skeletal, robot, weapon, mecha, no humans, science fiction, gun, holding weapon, glowing, holding, red eyes, a scifi  illustration  by  tsutomo  nihei 