Hyakuya, Mikaela

Mikaela is kind and upbeat in spite of the harsh events in his childhood, when he was abused by his parents and then dropped out of a car. He was then taken in by the Hyakuya orphanage. He was able to keep smiling and be happy because of his adopted family at the orphanage and even managed to befriend the extremely stubborn Yu. Mikaela was shown to be cunning. He allowed Ferid Bathory to drink his blood in exchange for good food, but Mikaela's true purpose was to steal a map in order to escape with the other children.

Once a human, Mikaela was turned against his will into a vampire by Krul Tepes.

He wields a sword that when he orders it to drink his blood, it sprouts thorny vines that pierce his hand. As the sword drinks his blood, the blade turns red. His strength and speed grow in proportion to the amount of his blood the sword drinks. As a vampire, he has incredible strength and regenerative capabilities. He can reattach limbs at will. Only a weapon containing a powerful demon can halt his regeneration.

The downside of his power is that he is dependent on Krul's blood, which is becoming increasingly ineffective at quenching his thirst. When starved for blood, he will lose control and attack Krul or a nearby human. Krul and Ferid warn him that going without blood for too long will turn him into a demon.

He is the only vampire shown so far to have blue eyes instead of red eyes.

In Chapter 36, after being forced by Yuuichirou, Mika drinks his blood for the first time.

(Source: Owari no Seraph Wikia)