Yu (Homunculus)

Yu is the name given to a homunculus by Mikaela, where both are characters in the world of the Seraph of the End series. Existing in the prehistoric past, Yu the homunculus was around with Mikaela during the era when dinosaurs roamed the Earth where they were seen in a seraph civilization. This specific homunculus would come to work very closely with Sika Madu for his seraph resurrection based plans.

Appearance
The most distinct feature about it was the single large eye in the centre of its being, which is its main means of expressing emotions. While the sclera was white, both the pupil and iris were dark in coloration. Additionally, it was a spherical based entity. Capable of appearing in a smoke like form, as well as from from a black circle seemingly into Space, like other homunculus it could also appear as a more solid ball. Able to open and close its eye, the homunculus also turned its body side to side, and up and down to indicate a no and yes answer respectively.

For what its skin was made of, it was dark in coloration but able to reflect light and refract it in parts. Able to expand dramatically in size, the homunculus could appear to become as large a moon. From its body, multiple long thin tendrils split at the end like fingers could be used to dextrously interact with various objects at the same time. A single shadowy wisp was another means of connecting itself with others.

In sustaining damage, the homunculus could be blasted completely apart. Tears similar to a burst balloon may indicate a hollowness to its being. Able to exist in some unseen state despite its apparent destruction, upon darkness being made the homunculus could materialize in a form remarkably similar to a black sun. Before appearing in a misshapen circle form with a specks of light emanating from a bright core, the homunculus could become its regular state once more.

Upon passing objects such as a coffin out its body, an opening could appear out of the homunculus' lower section to allow this. Expelling something such as a wholly developed human child left the homunculus appearing ruptured at its based. Parts of it seemed to drip in an indication of the fluid like component to its essence. A small aspect of itself could break off and act as an individual being. Accordingly, the main part of the homunculus could engage with Sika Madu in one area, where the droplet detachment could tend to the different matter that Mikaela wanted to discuss elsewhere.

Personality
Partaking in a game of hide-and-seek, Yu the homunculus awaited Mikaela to find it as it hid inside a living lizard. Patience and commitment was apparent in a greatest game of hide-and-seek, namely becoming the corpse of Mikaela so that Sika Madu would not succeed in resurrecting him. Apparently excited, it communicated this non-verbally by bouncing around before Mikaela. Its interest in what others are saying is shown by maintaining its gaze at them.

Sentient and also able to read basic and advanced words, the homunculus had also apparently read information that Sika Madu was hiding from Mikaela. It was intelligent to recognise facial expressions and know what Mikaela was inferring from one look. The homunculus understood a complex plan detailed by Mikaela for them to switch places, which was carried out convincingly.

For all the exceptionally sensitive information the homunculus has access to, it does not reveal it to others right away, if ever. The same applies for when it can seemingly make out that Yu and Mika are in the area. When it outright can see Yu and Mika within a memory it makes no mention of this to Sika Madu who is alive in the present time and who can also access past memories. Very discreet, the homunculus complies with Mikaela's request to join him quietly, and carries this out unnoticed by breaking off a part of itself to head over and engage with him.

Not forthright in answering Sika Madu whether it had saw everything he experienced, the homunculus' actions are a means of communication. Asked perhaps rhetorically how Sika Madu is to collect the power he needs for resurrection, the homunculus responded by having the coffin of Mikaela slide out of it as the correct answer.

Very efficient, the homunculus is ready at once to carry out orders without any delay. Tasked with darkening rings of light, the homunculus blasted its way upwards to begin right away. When cursed dolls needed to be made, the homunculus generated multiple humans. For the plan to connect his soul with Mikaela and assume his form, the homunculus apprently had reservations given the suddenness but confirmed it was not willing to abandon Mikaela as his friend. The homunculus promptly carried out the process of connecting their souls, and scattering the sinful keys.

History
Although not seen, Yu the homunculi was hidden inside a small lizard amongst some trees. Upon being found by Mikaela, the homunculus flew out the lizard's mouth when it was opened. Animated, it bounced around in apparent excitement while Mikaela stated he knew right away where it was hiding. When Mikaela spoke for it to come since father was calling, the homunculus was on his shoulder and flown towards a smoking mountain in the distance.

Within the seraph civilisation, Yu is levitating beside Mikaela with its gaze fixed on the ice cream he is carrying. Rather than placing itself on his shoulder, this time Yu flies upwards with him through the air. They both make their way to an opening in the side of the very tall and thin building rising from the seraph civilisation far up into the sky. While doing this, Yu is looking ahead to their destination.

At the reported top floor of the Tower of Babel, the homunculus floats slightly above Mikaela as he greets his father Sika Madu. Ever-silent as they speak, the homunculus physically reacts to being spoken to by Sika Madu after hearing that it was told by him to keep an eye on Mikaela. Its name mentioned by Sika Madu, it is close to Mikaela who is joyful that it has been given the name Yu and takes to looking at him. From Yu the homunculus' perspective it regards Mikaela's happy expression.

Observing Sika Madu as he details that naming a thing could curse them with a heart, it appears to listen further as Mikaela hears he was named by his father to curse him. While Mikaela has taken to embracing Sika Madu and seeks to clarify that he is joking, Yu the homunculus' gaze turns to something else. To the side, the homunculus is able to discern that Yu and Mika are present in this scenario.

After Mikaela has fallen ill, the homunculus looks at him as he kneels on the floor. It watches both Sika Madu and Mikaela as they discuss how they would each feel upset at the current situation of illness. It draws closer to Mikaela when he is happy to head to the cleansing room and goes there with him.

Within a room at some location, the homunculus floated over and looked in Mikaela's direction as he rested his head on Sika Madu's lap. It maintained its position over the bed they were on as Mikaela and Sika Madu spoke about going outside, and when going on a picnic was mentioned. Its concentration was on them as the discussion took place.

Watching Sika Madu leave the room, the homunculus then looked to Mikaela who was happy to speak about the picnic. When Mikaela said that it should come with them too, the homunculus considered this for a moment before having an expression of uncertainty.

When Paimon entered the room and meant to attack Mikaela with a knife, the homunculus acted first and moved itself in the way. Positioned in between them to protect Mikaela, the homunculus was struck by a light based power from Paimon and sent crashing into the wall.

For what the homunculus' fate was after being struck, whether resurrected or summoned it could be formed out of portal of Space that Mikaela's coffin was lowered into. The circular opening became a spherical ball after Sika Madu spoke for light to hide from God's sight and become darkness. Sounds were involved as the homunculus opened its eye.

Informed at once that Sika Madu was going to resurrect Mikaela and bring everyone back, the homunculus was directed to take all the light in Babel and convert it to darkness. Just as rapidly, the homunculus was able to blast its way out the tower, and propel itself upwards.

Raising itself to Space, the homunculus was before the many floating halos of light around the Tower of Babel. Gazing at one, the homunculus was able to gradually darken the light ring until it became fully black. From its influence, the dark ring then was seen to contain a row of individual eyes that resembled its own. Having grown to a huge size itself from this process, the homunculus was visible from Space to those on Earth such as Amon and Astaroth.

From the now colossally large homunculus were multiple long tendrils that were attaching themselves to the black halos. Where seraphs armed with trumpets had appeared around it, the homunculus looked to their presence. Tending to its duties, the homunculus then found different rings of lights form from the seraphs' trumpets. From a fracture in the dark centre of Space, the homunculus was blasted by a thick beam of light and blown apart.

While apparently destroyed, it is possible the homunculus was able to view a humanoid angel and the seraphs that attacked it go on to destroy the civilization on Earth that it had lived in. Seemingly unable to form for millennia until Sika Madu was able to produce darkness, Yu the homunculus was able to materialize as a light within shadow before taking its form.

Addressed by its Yu name and after being questioned whether it saw everything, the homunculus had a subdued reaction. It took to looking at Sika Madu before he spoke how he could resume his resurrection campaign given he could no longer touch light anymore having become an undead. Asked how the power for resurrection is to be gathered now, the homunculus responded by slowly dropping the coffin containing Mikaela onto the ground.

As its base opens for the task, the homunculus observed before beholding the coffin that lay before it and Sika Madu. The homunculus listened as Sika Madu detailed a plan to resurrect Mikaela to access the light within seven keys he holds in order to resurrect others.

Once Sika Madu decided that copying God was the best way, the homunculus was part of a joint effort to create cursed dolls made out of mud who could collect darkness. Shimmering with light after being physically touched by Sika Madu's hand, the homunculus watched as it somewhat violently expelled a fully formed human child with dark hair from its base.

Whether from Sika Madu's comments on creating humans, or beholding the first one it has made on Earth, the homunculus wobbled with enthusiasm at some matter. It may have been the reaction of a second human in the process of being formed as shortly after the homunculus would eject another youth with light colored hair. The bubbling like base of the homunculus would then produce at least thirteen other children for fifteen in total seen. It dropped them on the grass where the grave markers of angels were within view a short distance away.

As the children registered their new surroundings, the homunculus focused on Sika Madu. Touched by Sika Madu again, the homunculus was directed to make these humans greedy. Having them ephemeral, with melancholy, and strong as well were other features to instil in them. The homunculus was part of a further phase of the plan to place the souls of deceased angels into the humans, then have them breed and prosper to have more to gather darkness.

Where it would appear that the souls of angels had rose up to fly into the human children, the homunculus with Sika Madu was apart from them all as it engaged with him. Engrossed by what Sika Madu was saying, the homunculus did not appear to notice that the first child it created had approached the coffin of Mikaela and could hear from him.

In the process of creating humans, the homunculus continued its duties to also have angel spirits fly into them. It dropped two children at the same time, of which it seems probable that one child had the spirit of Paimon within, and another child had the spirit of Bael. The homunculus was seen engaging with Sika Madu.

When the spirit of Mikaela had entered the body of the first child it brought to Earth, the homunculus was called to by him. Able to hear Mikaela within the boy speak its name where Sika Madu nearby couldn't, the homunculus reacted to the whispered request to come over here quietly. To achieve that, the homunculus broke off a droplet of itself which floated over to where the youth was stood near the coffin, yet kept its larger complete self near Sika Madu to ensure discretion.

The smaller aspect of the homunculus appeared before Mikaela who was conscious in the human boy's body and blinked an eye open. Hearing that Mikaela had his own plan, the homunculus used a sound based communication to indicate its engagement. Where Sika Madu was not to know about the plan, the homunculus heard Mikaela state that someone else had to become "Mika" in his place.

After a pause where the homunculus was apparently unsure who Mikaela had in mind to assume his place, the homunculus registered from his look that it was to be the Mika imitation. Startled at the plan, the homunculus seemingly protested the idea. Hearing from Mikaela that it is not what is said before, the homunculus is asked whether it remembers that it promised to stay with Mikaela and protect him for his whole life.

Questioned if it was just going to abandon Mikaela, the homunculus considered the idea before swaying its body side to side to indicate a no answer. After Mikaela stated that it would never abandon him as they were best friends, the homunculus nodded in response.

With Mikaela commencing a plan for them to connect their souls together for Yu and Mika to be one, the homunculus extended from its body a wispy shadow to connect with the one from Mikaela in the human boy's hand. As that sizzled while the connection was seemingly made, the homunculus heard how he and Mikaela would have to go against father. Where Sika Madu was really smart, they were going to have to get serious if they wanted to get the better of him.

For the plan to switch places, Mikaela was to forget that he was Mika and become "Yu" completely. The homunculus was directed to do the same, forget everything and become Mikaela as of now. Seemingly doing so, the homunculus was told that so long as it was a convincing "Mikaela" then father would never succeed in resurrecting Mikaela himself as his soul was really in the human body.

Framed as a fight getting started, Yu the homunculus was addressed as Mika now as the plan was underway. In the end, Mikaela's goal was to save everywhere where it would just be the homunculus and him as a team. Asked if it would stick by him, the homunculus contentedly closed its eye and nodded its body to respond affirmatively.

The absence of the shadowy connection between them may have indicated their souls were together at this point, and the homunculus was directed by the soul of Mikaela within the human boy to jump into Mikaela's physical body inside the coffin next to them. The homunculus was to take the seven lights inside of Mikaela's body and send them flying out into the world where father could not reach them. That way it would take even longer before he could try and resurrect Mikaela.

Using a sound to indicate that it understood, the homunculus focused on carrying out Mikaela's directive and made no indication to Sika Madu of what was afoot when he had noticed who he saw as a human boy near Mikaela's coffin. As Mikaela erased his own memories, the small fragment of the homunculus entered Mikaela's corpse. Opening his eyes, the homunculus animated the corpse to break out of the glass top of the coffin with Mikaela's wings outstretched.

In response to the soul of Mikaela within the human boy bidding it farewell and promising to collect all of it, the homunculus inhabiting Mikaela's corpse also used it to speak a response. Agreeing that okay it was a promise, the homunculus ended its sentence partially by calling him Mika, before changing it to Yu as per the new identity.

"Okay! It's a promise! Mi- Yu!"

- The homunculus inside Mikaela's corpse makes a promise to Mikaela's conscious spirit in a human body who it then addresses as Yu as part of their plan.

Shimmering with light all around Mikaela's body, the homunculus successfully cast out what were seven sinful keys in all directions. The main body of the homunculus was giving a show of indicating nothing amiss by continuing to bring forth humans to the world. Whether it feigning to not understand what Sika Madu meant when questioned what did it do, or because the homunculus had erased its own memories at that point, the being appeared quizzical when spoken to. It used a sound based answer to respond to Sika Madu.

Not acting at all when Sika Madu murdered the child that had Mikaela's soul within, though without memories now, the homunculus as ever carried out Sika Madu's orders to bring humans to the world. One such child was dropped and did not appear to have an angel spirit fly into it, but was notable in any case since the child had the feeling there was something they needed to do. It is possible the homunculus brought forth another human with Mikaela's memoryless soul inside.

Story
Where Yu and Mika exist in the present time they have established themselves in the Sea of Trees around Mt. Fuji where they mean to access past memories. This memory of the prehistoric past is one able to be accessed. Like them, this particular homunculus appears unique among others of its kind, along with Mikaela and Sika Madu, in that it is able to also detect their existence.

The homunculus' activities, from defending Mikaela from Paimon and producing children, two of who resemble Yu and Mika, are observed by them both. Where the homunculus was seen by them again in the area where it created the first humans seen on Earth it made no indication that it could see Yu and Mika at that point in the memory.

Its activities are also observed by Saitō who has managed to access Shikama Doji's memories from his prison in the modern day Japanese city of Shibuya. Unlike Yu and Mika before in the Tower of Babel memory, the homunculus does not indicate whether it knows that one of the second progenitor vampires is viewing memories.

Powers and Abilities
Seemingly having the power of possession, the homunculus could enter and conceal itself within a living being. It could also enter a deceased individual's body without any breakages to the skin upon its entry. Animating a body as it did with Mikaela. the homunculus could use bodily functions such as a human's means of talking to speak to others using words. Its ability to form itself into a shadow based substance likely enables it to conceal itself within a smaller entity such as a lizard. While it could hide itself visually from Mikaela, it did not display the capabilities of being invisible to other senses he had. Naturally airborne, it is presumed that like others the homunculi could carry itself through the air at various heights and distances.

From within its lizard host the homunculi could apparently use it to stare in the direction of something it could see. Its ability to perceive things made it the only being from the prehistoric past to be able to make out that Yu and Mika were within the Tower of Babel with them. Other homunculi in the seraph civilisation did not show this ability to be able to perceive viewers from the far future.

Having the strength to break through a structure such as the Tower of Babel, the homunculus also had the means to blast itself upwards at a tremendous speed and breach Earth's atmosphere. Able to exist in Space, the homunculus could move itself freely there too. For what its body could not endure, the homunculus was split apart by a seraph generated beam of light.

From looking to a ring of light the homunculus could darken it completely. Either from its own input or forming others the ring of now darkness could have eyes resembling its own appear. Extensions from the homunculus could be used to interact with objects namely an amount of shadowy like tendrils that could attach themselves to rings of light. Perhaps absorbing this energy, whatever the case the homunculus could exponentially increase its size to appear as a moon visible from Earth.

Even after being destroyed physically, the homunculus could seemingly reconstitute itself to acquire the coffin of Mikaela a very short time after. Further, it was capable of storing such a large object within its body. Rather than any size affecting abilities being used on others, it likely a portal based ability to transfer objects where it wanted. The homunculus could drop the coffin containing Mikaela without the body being moved from place.

Upon contact with Sika Madu's light-enveloped hand the homunculus was able to produce human children. Whether outright created or transported from another location, the homunculus could rapidly bring a large number of children of different genders and skin tones to establish the first known presence of humans on Earth. Though some non-contact means, but again with Sika Madu's intervention the homunculus seemed capable of installing emotions in humans, namely having them greedy, to granting traits such as melancholy, to making them ephemeral and strong.

From the words used this being had a soul, and the homunculus was capable of connecting it with another individual's soul. A small shadowy tendril was the means of enacting this, where the homunculus could connect it with an identical one from Mikaela for their souls to become one. Like Mikaela, it appears the homunculus also had the capabilities of erasing its own memories. It could possess Mikaela's corpse to scatter the seven lights inside across various points of the planet.

Mikaela
Having been tasked with observing the First's son, Yu the homunculus went along with his escapades such as playing hide-and-seek and acquiring ice cream with him. Close to Mikaela, it would rest on his shoulder as they returned home together. Yu the homunculus would focus on the ice cream Mikaela had as well as regard him with a similar apparent fondness. Having been given its named "Yu" by Mikaela, it allowed itself to be handled and squeezed by him. Where Mikaela did not like the cleaning room, Yu went there with him. When Mikaela was assailed by Paimon, it acted to protect the former from attack.

Generated again, the homunculus set about darkening light where it was involved with an attempt to resurrect Mikaela. While it would be attacked before it could carry this out, the homunculus sought out and acquired Mikaela within his coffin and kept it safe from a joint seraph attack that destroyed the seraph civilization. For millennia the homunculus apparently kept Mikaela secure to present him before Sika Madu when he regathered his means to attempt his plan in a different manner.

It would be clear that the homunculus was especially close to Mikaela where there was empathy for him. When Mikaela was in the body of a human, the homunculus came over at once at his request and interacted as normal. From what Mikaela said, at some point the homunculus had told him that it promised to stay with him and protect him with its life. Questioned if it was just going to abandon Mikaela, the homunculus communicated no where it would never do so as they were best friends.

With Mikaela the homunculus would pull off a pivotal campaign. Connecting their souls together, the homunculus was to become the corpse of Mikaela, where Mikaela's soul would be kept within a human. From this, the homunculus would help prevent Sika Madu from ever resurrecting Mikaela as his soul was really in a human's body. The homunculus helps Mikaela with his plan to resurrect everyone his way never mind the eons it may take. Satisfied that it is just the two of them as a team, the homunculus also entered Mikaela's physical body in order to cast the sinful keys across the world at Mikaela's behest.

Sika Madu
At some point, the homunculus had received a directive from who would be the future first progenitor of the vampires. At being spoken to that he was told to keep an eye on Mikaela, the homunculus reacts yet does not look at Sika Madu. Apparently hearing everything the First says to his son and understanding it perhaps better than Mikaela, this homunculus had also apparently read the information the First had tried to conceal.

Brought back into being by Sika Madu and referred to by its Yu name now, the homunculus complied with his orders to commence a resurrection plan. When Sika Madu was able to conjure darkness again, the homunculus formed and may have observed everything Sika Madu endured in the millennia he was cursed alone on Earth. The homunculus was ready to answer how they could resurrect others now by producing the coffin of Mikaela.

The only sentient being around Sika Madu at that point, the homunculus was used to bring forth the first child viewed on Earth. Multiple other children were made in Sika Madu's goal to have them gather darkness for resurrection. Ready to efficiently help with that, the homunculus was seemingly also fine in instilling emotions Sika Madu wanted the humans to have.

Incredibly helpful to Sika Madu for what it had done, and was able to do, the willingness to carry out his directives appears to have formed a natural working rapport between them. It reached the extent where the homunculus was engaging with Sika Madu to the point that neither of them noticed that the deceased Mikaela was communicating with one of the human children nearby.

Working very well with Sika Madu, but in a different way, the homunculus did not reveal that his son's soul was alive, neither did it impart that it was capable of bringing forth the seven lights within Mikaela.

Yūichirō Hyakuya
Sharing a first abbreviated name, the homunculus could perceive this human member of the Moon Demon Company who lives in the present time and was accessing a memory where it existed in earth's prehistory. While capable of communication, the homunculus neither engages with Yu or informs others that he is there. The first human the homunculus would produce on Earth was a young boy who resembled Yu.

Mikaela Hyakuya
Where Mika was a demon when the homunculus was first seen noticing him, he is someone who physically resembles Mikaela. The homunculus sees but does not act on Mika's presence in the memory. This is all the more striking since as well as being watched by those from the future accessing a memory, the homunculus would have seen Mika's active demon traits such as his horns and tail which were not a sight it may have come across before. It is not clear if the homunculus knew it was looking at what was likely supposed to be a future vessel for Mikaela's soul.

Paimon
When Paimon attempted to murder Mikaela the homunculus did what it could to defend him. If it was outright destroyed by Paimon's light based attack the homunculus could reform later. The homunculus would bring forth a human that appeared to contain Paimon's soul though without memories of his life as an angel.

Seraphs
As with other homunculus, this one paid no specific mind to cloaked seraphs that it shared a civilization with as it remained near Mikaela. In adhering to Sika Madu's orders, the homunculus acted to try and resurrect the seraphs who had perished from a plague. Due to what it was capable of, the homunculus was tasked with placing angel souls into humans it had just created which it did. This was done for human appearing angels where it would appear that at least Paimon, and Bael's were placed into a human.

Humans
Millennia after the seraph civilization fell, the homunculus obliged with Sika Madu's attempt to create cursed dolls out of mud and the first human seen on Earth is what ruptured out its base. Accordingly, in creating human children whole or bringing them from another location, this one homunculus appeared responsible for establishing human life on Earth.

The homunculus appeared capable of altering human emotions. It could induce feelings that Sika Madu wanted in humans, namely greed and melancholy. Further, it seemed able to affect humans by having them transitory and strong. Directed to place the fallen angel souls in humans, the homunculus was also resorted to in order to have humans breed and prosper.

Quotes
"Hyooie hyoop! Hyoop!"

- The homunculus is capable of verbal communications of which these coincided with it apparently being surprised. "Hyoop" is the most prevalent sound made often by itself. Its communications are able to be understood by Mikaela.

Trivia

 * First seen in chapter 123, the shadowy eyeball being would have its species name revealed as a homunculus in chapter 125. Further, this specific homunculus would be named Yu.
 * Not specified whether it is the same, but the eye existing within Yu's memories has also witnessed events Yu can recall.
 * In chapter 129 the homunculus materializes in a form virtually identical to a black sun.