Create a striking image of a realistic ninja in mid-action, poised to strike with a katana in an urban environment. The ninja, dressed in traditional black attire with intricate details, showcases a fierce expression of concentration and determination. Their body is in a dynamic pose, with one leg extended forward and the katana raised high, ready to deliver a powerful blow. The background features a blurred urban landscape, with hints of buildings and alleyways, creating a sense of movement and context. The lighting is dramatic, casting shadows that enhance the ninja's form and highlighting the gleam of the katana. The overall color scheme is bold, with deep blacks contrasted by the metallic shine of the weapon, making the design visually striking for a t-shirt.