Akaei's appearance is that of a red stingray with a single yellow eye, fourteen pink markings, seven on both pectoral fins, and a pair of small pelvic fins beside the tail. Her underside is pale yellow, it has the same fourteen markings in the same placement and a mouth shape like an inverted "v". Despite her younger age, she is still enormous enough to cover a large area under her body.
Akaei are titanic fish that resemble stingrays that live in the Pacific Ocean. Their bodies can reach in the length of 10 to 12 kilometers. They spend most of their lives on the ocean floor, where every now and then they rise to the surface to shake off the sand and rocks, that they have collected on their backs. During this process, because of their great mass, they create a maelstrom that displaces huge amounts of water. Sailors frequently mistake them for islands when they surfaced, leading to an unfortunate fate. If their ship gets too close to one that is surfacing or sinking, then they will be swallowed and destroyed in a great wave or sucked down in a whirlpool to the bottom of the sea. Ehon hyakumonogatari, a picture book of strange tales published in 1841, is where Akaei's description comes from.