Son of Mine

Son/Brother of Mine was the leader of the Family of Blood.

Biography
Having possessed the body of Jeremy Baines from Farringham School for Boys on 10 November 1913, he led his family in a chase to catch the Tenth Doctor to gain his immortality. Otherwise, they would die in three months' time.

After the Family's defeat the next day, the Doctor suspended Son of Mine in time and had him watch over the fields of England as a scarecrow.

Noticeably, he spoke in a way that made many of his consecutive sentences run together. After possessing Baines, Son of Mine appeared able to keep his eyes opened all the way most of the time. Perhaps as a side-effect from possessing Baines, the right side of Son of Mine's face was nearly always in a half-smile.

He was probably the most intelligent of his Family, which would explain why he took charge of the Family. (TV: Human Nature / The Family of Blood)

Personality
Son of Mine was highly intelligent, intensely sadistic and extremely callous. Like the boy he possessed, he was arrogant, ruthless and sarcastic. He was brave and sly, as he was unafraid to kill anybody if it meant that he would achieve his goals. He was cruel, dry and heartless and had a taste for blood. Nevertheless, he did seem to have a soft spot when it came to his family, specifically his sister, as shown when he expressed the hope that the Doctor would one day forgive her and free her from the mirror in which she was imprisoned. (TV: Human Nature / The Family of Blood)