Mikaela

Mikaela (ミカエラ) is a character referred to in Seraph of the End. The physical body of Mikaela himself was kept during the dark ages of Greece. There were candidates believed to have the Michaela trait. While Mikaela is seen deceased, he is Sika Madu's son and heavily involved in his long-term plan to be resurrected.

Appearance
The Mikaela seen in the past was stated to be deceased but was well preserved and appeared like an adolescent. He had long wavy, light colored hair nearing his shoulders, and pointed vampire-like ears. Most prominently were four large feathered seraph wings on his back. He bears a remarkably similar appearance to Mikaela Hyakuya as a child.

With Yu seeing a glimpse of Mikaela's face, he was under the impression that he was a pretty girl but with Mikaela having no clothes on, Noya referred to Mikaela as 'him'. When Yu mentions that Mikaela could be a princess to be rescued, Sika Madu remarks neither he or Mikaela have a gender like humans. While he cannot say whether or not Mikaela can become a proper "princess" when Yu refers to him as that, Sika Madu still uses 'he' when referring to Mikaela in conversation.

In terms of the being Mikaela may be, his father Shikama Doji is seen to have blue blood. From what Guren feels he knows, the price to resurrect the First's son would be the same as what it takes to bring back all of humanity. Seven sinful keys, and the lives of every last vampire appears to be what is required to restore what Mikaela is.

Personality
Supposedly, Mikaela has been speaking to Yu and he is described as super nice.

History
The physical body of Mikaela was around at some point during the Dark Ages of Greece. His corpse is held in a large see through coffin within in a large room, off limits, and is observed by Noya, Ashera and Krul. Noya comments he was "what all of us were meant to become but failed" and they figure what to do about the Mikaela. He is also seen by a young Yu and although stated to be deceased, Mikaela's mouth had opened slightly during the period that others were observing him. He is later referred to as Sika Madu's son.

Within a room containing clear fluid filled tanks, Mikaela is observed in his coffin by Yu as a child. Unresponsive to the happy calls that it is time to wake up, Mikaela is referred to as a princess to be rescued by Yu. Where Sika Madu mentions that a kiss could not bring him back to life, it is also commented that more time, with more sacrifices would be required. With Yu having a secret, he tells Sika Madu that although Mikaela is dead, sometimes he will still talk to him. Where he has not spoken to Sika Madu in eons, Mikaela is planned to be brought back to life by Yu and Sika Madu. When Sika Madu and Yu were discussing matters around his coffin, this scenario was observed by Ashera.

Shibuya Arc
In the present time Noya is surprised upon seeing Mikaela Hyakuya and excitedly wonders if Sika Madu succeeded in creating a Mikaela.

Post-Shibuya Arc
Visualized when Saito is speaking to Lest Karr about the third progenitors, Mikaela is seen within his coffin in the centre of a pillared room. Surrounded by Asuramaru, along with Byakkomaru, then Gekkouin, also Kiseki-o, Raimeiki and Noya, above him floats a ring of Black Suns. In this location, Mikaela had Sika Madu carrying a seemingly unconscious Yu towards him.

When Mika is a demon with no memories of himself and makes contact with an eye he comes across, a memory of Mikaela's coffin within the room filled containing clear fluid tanks is viewed. Where he was deceased, Mikaela did not react to Yu coming in and calling for him to get up. Neither could he respond when Noya remarked that Yu was to be the sacrifice to bring him back from the dead. His coffin was covered with Yu's blood after Noya murdered him. In this memory that Demon Mika is accessing, that Shikama Doji has joined, the coffin is absent as electricity surges outwards after Demon Mika agrees to become Yu's demon.

Akihabara Arc
Mentioned by Saitō, it is gathered that Shikama Doji wants to bring Mikaela back to life as he was his son. Vampires including Urd, and third progenitors such as Lest Karr, and Krul Tepes were guessed to be test subjects to see whether they were strong enough bodies to house Mikaela's soul. He is referred to again when Saito questions the First whether Mika is a vessel up to the standards of allowing his resurrection.

In a discussion how Mikaela must be the same species as Shikama Doji, while Saito is unsure of whether he is an angel or demon, the price of resurrecting one would be unimaginably large, enough that the seraphs would punish the attempt. Mikaela's resurrection is to be thwarted by Saito, along with Urd, then Lest Karr and Ky Luc at least who are wary of a potential second destruction of the world.

After Mika has regained his memories as a demon and been rescued, Yu shares how he has memories from before he was born. In some really old ones and due to the resemblance, Yu says he remembers seeing Mika's corpse where Mikaela is visualized.

Sika Madu
His father, Sika Madu was the first vampire and kept his body preserved during the dark ages of Greece. By the present day, Shikama Dōji states that he is trying to save him, as Mikaela is his precious son. Said to not have spoken to him in eons on account that Mikaela is deceased, he is stated to be cared for by the First, where he is planned to be restored to life.

Mikaela Hyakuya
At seeing Mika, the demon Noya is under the impression that Sika Madu succeeded in created a Mikaela. They are physically similar as children, yet Mikaela's ears were pointed where Mika had human appearing ears. Mikaela's corpse would have been available to see by Demon Mika were he not focused on other parts of a memory. When Mika arrived at the Hyakuya Orphanage, Saito also noted the resemblance and questions if this is a vessel for preparations for Mikaela's resurrection.

Yūichirō Hyakuya
When lying deceased in his coffin, Mikaela was found by Yūichirō Hyakuya who joined the forbidden room that Ashera, Krul, and Noya were in. Visited more than once by Yu who was fond of him, apparently Mikaela had been speaking to him.

Noya
His corpse is observed by Noya when he was a vampire in the ancient past. Mikaela is regarded as what he and others were meant to be but failed.

Ashera Tepes
After Ashera Tepes became a vampire, Mikaela's existence and that he was Sika Madu's son became known to him.

Krul Tepes
When Krul Tepes entered the forbidden room that Mikaela's corpse was kept in, his being was seen by this vampire.

Saito
That he is the First's son is known to Saitō, a second progenitor vampire who has been tracking Shikama Doji. Due to his relation to the First, who Saito seeks to undermine, and because of the nature of his being, Mikaela's potential resurrection is not something Saito wishes to see enacted.

Urd Geales
The other second progenitor vampire, Urd Geales, where Mikaela's resurrection may rest on his actions where he is against it.

Lest Karr
Third progenitor Lest Karr, who was seemingly discounted in Sika Madu's plot to help resurrect Mikaela. Due to what his resurrection might bring about, Mikaela being restored is not something Lest Karr is in favor of.

Ky Luc
His fate influenced by Ky Luc, a fifth progenitor, Mikaela's resurrection may be affected by his actions against the event.

Trivia

 * When Noya, Ashera, and Krul discovered the corpse of the winged being Mikaela, Noya called Mikaela "what they all were meant to become but failed to", implying the true nature of the Mikaela trait.
 * Due to the four large feathered seraph wings on his back, it is possible that Mikaela is a seraph.