Sawk is a bipedal, humanoid Pokémon with a lean, blue body and rocky skin. Its head is oblong-like and low on its shoulders, with an ornate sideways z-shaped black feature that forms its nose and its left brow. Its hands and feet each have three digits, with its feet and toes coming to a sharp point. It wears a light blue karate gi with a black, v-neck collar that extends down to its black belt. Sawk will tie this black belt to increase its power. The gi has an intricate diamond pattern on its sleeves and a black, square patch on the bend of its knees.
Sawk is found secluded in the mountains where it trains to increase its strength. It becomes angered if it is interrupted while training. A Sawk that has trained to its fullest potential has enough power to cleave oceans with a single karate chop. This Pokémon is an all male species with no female counterpart.
According to interviews with Ken Sugimori in Nintendo Dream, Sawk is based on a karateka (a karate practitioner).
During development, Sawk and Throh both had horns, which may hint towards their design being originally based on oni. However, they were replaced with eyebrows so as not to clash with Tornadus and Thundurus, who were originally designed to be red and blue, like Throh and Sawk.
Sawk's single eyebrow is likely a remnant of a single horn from its early design, although it could be a reference to an anecdote involving Mas Oyama, a well-known karate expert. It's said that while training in isolation, Oyama was told by his mentor to shave off one eyebrow to resist the temptation to return to society.
It may also draw inspiration from namahage, demons wearing oni masks, replacing the mino with a karategi.
Sawk may be derived from sock (to punch).
Dageki may be a combination of 打撃 dageki (blow, strike) and 鬼 ki (demon).