- "Development of psychic abilities stunted by fretful, morbid temperament. Inexplicable resemblance to an Ingmar Bergman extra."
- —The Monocle[src]
The Séance, 00.04, Klaus Hargreeves. His powers consist of telekinesis, communicating with the dead (mostly through oujia boards), channeling them, communicating through the airwaves, possessing people and he can also levitate. He is known to be a heavy drinker and drug user, having apparently checked himself in a psychiatric hospital called Shinyview before the reformation of The Umbrella Academy. He dresses in a goth fashion most of the time, black clothes, black make up and he dyed his hair black at the beginning of The Umbrella Academy: Dallas.
In The Umbrella Academy: Apocalypse Suite, he stopped the White Violin's performance, distracting her by dressing up as Hargreeves and belittling her. Shortly thereafter, he stopped a chunk of the moon with his telekinesis.
In Dallas, he dies, but is quickly sent back to Earth by God, possessing and killing the men who tortured and killed him, and hereafter telling Number One its apparently no problem when "children of this family die", thus also raising the question if The Horror is truly dead.
It's also revealed he had a child in the three years spent in the past in Dallas.
The child that would become Klaus Hargreeves was born at the same time as forty-two other extraordinary children. As a baby, he was adopted by the world-famous scientist and entrepreneur Sir Reginald Hargreeves with the express intention of training them to save the world. Klaus lived at the special academy set up by Hargreeves to train the children. Designated as Number Four by Hargreeves, Klaus had psychic abilities including being able to contact the dead. He had a morbid and fretful temperament, and Sir Reginald found that he resembled an extra from an Ingmar Bergman film.
As a boy, Klaus was sweet and vulnerable. However, Sir Reginald experimented on Klaus more than he did the other children. The experience changed him, causing him to become crueler in Vanya's opinion.
The Umbrella AcademyEdit
Ten years after their adoption, the Umbrella Academy made their public debut to counter the threat posed by the Zombie-Robot Gustave Eiffel and the rampaging Eiffel Tower in Paris. Klaus was part of the team during the battle, and tried to use his abilities to contact an engineer in the spirit world to give them advice on how to stop the Eiffel Tower. The battle ended with the death of Eiffel and the launching of the Eiffel Tower into space. After the mission, Klaus joined the others having celebratory ice cream.
Following the death of Sir Reginald, Klaus returned to the Umbrella Academy. Meeting Luther and Allison outside, Klaus intended to try and contact the spirit of their father to complain about having his allowance cut off. Klaus was present for Number Five's explanations about how he managed to return from the future, and then attended Sir Reginald's funeral in the grounds of the Academy.
- The Umbrella Academy: Apocalypse Suite