benimaru (tensura), tensei shitara slime datta ken, artist request, official art, second-party source, 1boy, black horns, black sandals, closed mouth, collarbone, crossed arms, eye mask, facial mark, frown, full body, hakama, hakama pants, horns, japanese clothes, looking at viewer, male focus, mask, oni, orange eyes, pants, red eyes, red hair, sandals, scabbard, sheath, sheathed, short hair, simple background, socks, solo, standing, sword, sword on back, transparent background, weapon, weapon on back, white socks