Spring-heeled Jack

Spring-heeled Jack was a Hunter.

Searching for Morjanus
Jack was sent to Earth to kill Morjanus in 1837. He was unable to find her as she had taken on a false identity. He was given the name Spring-heeled Jack as he jumped around. He roamed London for three years trying to find her. He captured many women and searched them for a necklace that would identify them as Morjanus.

Meeting the Doctor
In 1840, while trying to search Penny Chapman, Jack was attacked by the Eighth Doctor who shoved a cart at him, this did not hurt Jack who then left. He followed the Doctor and Penny to her home and when the Doctor was all alone he unleashed a blast of psychic energy upon him. He saw the Doctor's thoughts and the Doctor used the blast to see Jacks. Jack was thinking of his home planet that was on fire and his kind that were dying. Penny then attacked Jack with a shotgun but to no effect. Jack then left.

Guardian Demon
Jack found Morjanus in the identity of Penny and used his psychic attack on her. He killed a part of her that was Morjanus but left Penny alive. He then stayed in London as its "Guardian Demon" declaring that his home planet was wonderful but had gone. (DWM: The Curious Tale of Spring-Heeled Jack)

Personality
Jack went mad searching for Morjanus and so always spoke in rhyme. He liked to scare police and civilians and often threatened them with his attacks. (DWM: The Curious Tale of Spring-Heeled Jack)