"...Understood. So...pudding is...happiness."
Prime Field Interference Manifestation (Code: Embryo and Central Fiction)
Amber (Blue with the Embryo)
Shin Yokozaki City (XBlaze)
Japanese pears (XBlaze)
Embryo Storage (エンブリオストレージ)
Es (エス), short for Embryo Storage is a major character in XBlaze Code: Embryo and the protagonist of XBlaze Lost: Memories. She is the current wielder of the Signati Gladio Crystalis: Murakumo. She is a Prime Field Interference Manifestation created by Souichiro Unomaru but is eventually turned into a human by Me.
Es is a short girl with amber (blue in Centralfiction) eyes, and blonde hair.
In XBlaze, she wears a button up shirt with a buttoned up collar, and two button square barrel cuffs, accompanied by a red tie. She wears an indigo, layered, underskirt, and over it, is a long white and blue skirt that buttons up, and has a blue ribbon-belt. With see through leggings that are a solid black at the toe, blue boots are worn over them. They shape into a v-line at the top, accompanied by a blue ribbon, and the soles are steel; there is a bow-tie at the end of her long braided hair. Over her outfit, she wears a light blue coat with a ribbon, and a sleeve band at the end of the sleeves.
In Centralfiction, Es' attire doesn't change much. The ribbon in her hair is removed, and now she wears a metal tip at the very end of the braid. Her shoes are now yellow, blue, and grey at the sole, and her white and blue skirt was replaced by a black dress with various golden buttons, and blue locks, while the her coat was removed entirely.
She doesn't exhibit those things known as emotions. She is coldly rational inside and doesn't care how she completes her mission. On the other hand, "those important to her" do remain in the depths of her memory, and she has thought deeply about them before. 
Es starts off completely emotionless and robotic. All that matters to her is the mission and even her own life is of no consequence. She is also unaware of a lot of basic human emotions like happiness, enjoyment and love as well as concepts like friendship and making up with others. However, as she spends more time around Touya Kagari and his friends, she slowly begins to develop emotions and thoughts of her own. Her first major step is eating pudding, which allows her to experience happiness and helps contextualize all of the emotions that follow. After Touya gets mad at Es for disregarding Hinata Himezuru's safety, Es first learns of sadness. This would eventually lead to her realizing that she is in love with Touya and she decides to disobey orders to protect him. Additionally, she comes to understand remorse for how many Unions she has killed and considers herself beyond redemption. By the time she inherits the Embryo, Es has developed a true human persona and willingly sacrifices herself to protect those she holds dear.
Powers & Techniques
As a Prime Field Interference Manifestation, Es possesses superhuman abilities. However, her body is flawed and requires maintenance every two days, otherwise she will start to degrade and eventually die. Additionally, even with her enhanced abilities, Es has clear limits, as seen when Drei was able to easily overpower her.
Thanks to a special system in her, Es can hear the Discover Call emitted when a Union uses their Drive. However, she can only hear them from up to 10 meters away.
In combat Es wields the Legacy Weapon Signati Gladio Crystalis: Murakumo. The sword is incredibly sharp, able to easily cut through a Union's crystal, which is otherwise thought to be indestructible. With her incredible reflexes, she is able to use the Murakumo to deflect high speed projectiles like Akio's ball bearings, Acht's ice and Ripper's knives.
After inheriting the Embryo, Es gained the power of god, Phenomenon Intervention. With it she was able to reconstruct a human body for Hinata and teleport her out of the Boundary. The power of the Embryo is so great that it can create recreate the entire world, undoing any event Es chooses, and even send people back in time. Furthermore, Es used it to remove herself from the timeline completely, erasing everyone's memories of her. The Embryo also allowed Es to create the World of the Tsukuyomi, an entire dimension capable of entirely sealing off a possibility from the Boundary. However, doing this used up most of the Embryo's power and only left it with enough power to turn back time via Phenomenon Intervention, unable to actually change destined events.
After becoming a normal human, Es lost most of her powers. However, her left eye had the remainder of Nobody's Phantom Memories stored inside of it. Using those Phantom Memories allowed Es to activate Phantom Memory: XBlaze, which, much like Touya's Awakening Release (XBlaze), used the stored seithr to increase her physical attributes dramatically, letting her keep up with Freaks. Unfortunately, this could only be used once and her eye returned to normal after that. It is ambiguous whether or not Es still has super strength or not. Mei believes she does since she can easily wield the Murakumo and once threw a man much larger than her, but Es disagrees, claiming the Murakumo is lighter than it looks and she merely used knowledge of leverage.
In BlazBlue: Central Fiction, Es is once again the Embryo Storage and, as the chosen guardian of the Gate, has access to the power of the Azure she was created from, making her much more powerful than before. Her Drive, Crest Arts, leaves trails of energy behind her sword swings, which then expand as a new attack. The Murakumo also has a new sheathe around it with the power to absorb and store seithr within it. Additionally, Es has the power to back up the data of those who have been absorbed into the Embryo, allowing them to be reborn in the new world created by Ragna the Bloodedge.
Also known as Embryo Storage. The gatekeeper of the Gate to the Azure, and the proxy that conveys the will of the Azure.
She backs up the chosen, who have lost their rights. 
An anti-ability warrior (aka Sleipnir) attached to the Mitsurugi Agency. Outside of combat operations, she is shockingly naïve and ignorant about the world around her. She rarely speaks or shows her emotions. In addition to her fighting prowess, she can also detect Discover Calls. She wields the Legacy Weapon, Murakumo, in battle. Ordered to protect Touya Kagari, bu Souichiro Unomaru, Es enrolled as a student at Hakuou North Academy and has moved into the Himezuru residence. A homunculus made by Unomaru, if she doesn't get special care every two days, her condition begins to worsen. If she stops functioning, her body is designed to rapidly disintegrate. 
An anti-ability warrior (aka Sleipnir) attached to the Mitsurugi Agency. Outside of combat operations, she is shockingly naïve and ignorant about the world around her. She rarely speaks or shows her emotions. In addition to her fighting prowess, she can also detect Discover Calls. In order to circumbvent what was once inescapable despair, she is resurrected as an ordinary girl in the real world. However, as a result of her resurrection she cannot remember anything about herself.