Embryo Storage

The Embryo Storage (エンブリオストレージ), also called as the Boundary Prime Field Device Manifestation (示現境界接触用素体), is an artificial life form, which is often referred to with the acronym "Es".

Es was created by Sōichirō Unomaru as a back-up vessel for the Embryo, but she failed to obtain it, which can be seen by her red eyes. She could go into the Boundary without experiencing any of its negative effects, and later she obtained Hinata Himezuru's Embryo.

Since Es returned from the Phantom Field as an ordinary human girl, she lost the Embryo Storage properties.