Eurus Holmes is born to Mr. and Mrs. Holmes and is the niece of Rudy Holmes. She is six years younger than Mycroft and one year older than Sherlock. She grew jealous of her brother's friendship with Victor Trevor and later abducts him and leaves Victor to die in a wishing Well (The Final Problem") Sometime later, she gloats to her brother that she drowned Redbeard and later burnt down Holmes Mansion. Because of the danger she had, Rudolph Holmes gets his niece locked in Sherrinford with Mycroft only knowing the secret. In order to spare his parents' feelings, Mycroft lied to his parents and said that she was dead. After Rudy died, Mycroft took it upon himself to take over the duty to watching over his sister.
Eurus also manages to take over Sherrinford and being able to come and go as she pleases
Series 3 Edit
Mycroft claims he holds no brother sentimental towards Sherlock, and claims they know what happened "to the other one" (His Last Vow). Later, Eurus sends the message with one of her recordings of James Moriarity in order to send a message to her brother.
Series 4 Edit
One day on the bus, John meets a woman named Elizabeth. John later ends up betraying his wife and begins cheating on Mary by sending the girl on the bus texting (which was something he would later regret). Eurus later tricks her brother Sherlock in pretending on being Faith Smith and goes to him for help. She later leaves him the next day. Sometime later she poses as John Watson's therapist in order to manipulate both men. Eurus reveals her identity to John, pointing out that she was the woman John met on the bus and the woman who posed as Faith Smith.
- Mr. Holmes (father)
- Mrs. Holmes (mother)
- Sherlock Holmes (brother)
- Mycroft Holmes (brother)
- Rudy Holmes (paternal uncle)