Mikaela Hyakuya is the deuteragonist of the anime and manga series Seraph of the End. He is the childhood friend of Yūichirō Hyakuya.
As an 8-year-old human child in the Light novels prior to the Apocalypse, Mika appears wearing short jean shorts. He wears a white hoodie over a collared shirt. Sometimes, he is also shown wearing an over-sized jean jacket. He has short, wavy blond hair and blue eyes, which gives him the appearance of a foreigner.
As a 12-year-old, being human livestock, Mika wears the standard livestock uniform. He wears the capri shorts and a hooded shirt. He is barefoot like the other livestock.
After becoming a vampire, he grows fangs, but his eyes remain blue. His hair hides his ears, so it is unknown if his ears are pointed or not.
In chapter 36 his eyes turns red after drinking Yū's blood.
- Anime: Livestock wear shoes in the anime. As a vampire, his boots have less decoration and appear completely black.
As a human, Mika is kind and upbeat in spite of the harsh events in his childhood. He is able to keep smiling and be happy because of his adopted family at the orphanage. He always thinks of his new family and is happy to buy ice cream for them. He is cheerful, feisty, and friendly and even managed to befriend the extremely stubborn Yū. He is a little violent and beats up Yū within seconds of meeting him. As the eldest child, he takes charge and acts responsible for the other children.
As he grows up in Sanigum, he becomes more cunning and willing to do whatever dirty work is necessary in order to help his family, but he refuses to let any of the other children take such hardships.
She turns him anyway, and he comes to hate both vampires and humans. He hates vampires because of his history with them, and he hates humans for using and experimenting on Yū.
As a self-loathing and moody vampire, Mika is a pale shadow of his former self. When Lacus asks him what he is, Mika answers that he is just an "ugly bloodsucker." He never smiles and always looks apathetic. Mika blames himself for the death of his family, and his sole reason for living is to save Yū. Ferid describes the vampire Mika as "overwhelmingly powerful and arrogant." Mika rushes into battle without any interest in glory, but he prefers to fight alone rather than have the other vampires backing him up. His arrogance and lack of concern for his own life have caused him to be extremely reckless on the battlefield, particularly when Yū is involved. After meeting Yū in chapter 12, he does not defend himself and lets Yu stab him through the chest. In chapter 14, Mika uses his own body as a shield to protect Shinoa from Yu, and Yu stabs him through the back at full power. The wound is severe enough to require curse detoxification. In chapter 35, he dives into a company of human soldiers and receives many injuries, and Shinya Hīragi stabs him through the back with his Black Demon Series weapon.
Unlike other vampires, Mika does not view the humans as livestock. However, he lusts after a girl's blood in chapter 5, attacks a young girl in chapter 26, and wants Aiko Aihara's blood in chapter 30 after he kills her. Ferid also tempts him with the blood of a young boy in chapter 22. Although Krul is the only person he bites so far, he desires human blood so badly that he can hardly stand it.
Despite the tremendous pain, blood lust, palpitations, and sheer agony of resisting the urge to drink human blood, he keeps control for four years. After he attacks a young girl in chapter 26, he manages to stop himself before drinking her blood but remains horrified by his vampirism. He wants to avoid drinking human blood until he rescues Yū from the humans but does not reveal what he plans to do after rescuing Yū, whether he intends to become a true vampire or die. Later on, it appears he planned to die, but Yu insists on Mika surviving and drinking his blood instead.
Mika is loyal to Krul Tepes and trusts her enough to capture Yū. However, he initially refuses until she explains what those purposes are.