Sachiel's appearance is tall, thin, and humanoid, it is slightly larger than an Evangelion, and functions both on land and in water. Its proportions are unlike those of a human; its arms are long enough to reach below its knees and its legs and feet are elongated and disproportionate. It lacks a proper humanoid head and neck, but like other Angels, contains a core in the center of its solar plexus. Its head is barely mobile and appeared to primarily be made up of bone and is structured much like a bird's, even having a long beak. After Sachiel regenerates from an N² mine attack, a second head emerges from its body, with a shorter beak than the first. Sachiel has red irises, which are able to be seen deep within its eye sockets. Sachiel possesses blood of a bluish-purple color, making it unique among Angels for whom blood has been observed.