Mikaela Hyakuya is a fictional character from the anime and manga series, Owari no Serafu or Seraph of the End. He was part of one of the Hyakuya orphanage with Yuichirou before the apocalypse. After being mortally wounded by Ferid Bathory, Krul Tepes, the third progenitor, turn Mikaela into a vampire in order to save him. He hate vampire, but hate human even more, he main concern is to found and save Yu from the Japanese Imperial Demon Army.
Mika used to be a cute cheerful little boy, but after the massacre of his family by Ferid, after being turn into a vampire by Krul against his wish (like if he was in position to choose anyway) and after knowing the truth behind the Hyakuya orphanage, he become moody and depressed.
He doesn’t care about the war between the Vampire and the JIDA, the only thing that matter for him is Yu safety. He want to found him and bring him far away from the imperial army, from those ugly human who did horrible experience on his only family.
He might not be as strong as Ferid or Crowley, but since he got transformed by the Vampire Queen of Japan, Krul Tepes, he is still quite powerful despite is young age.