Abel Magwitch is a character in the novel "Great Expectations" by Charles Dickens. He first appears in the story as an escaped convict who Pip encounters on the marshes. He frightens Pip into stealing food and a file from home for him.
When Pip brings Magwitch the food and file he requests, Pip tells him about seeing another convict on the marshes. Magwitch realizes this other person is his former criminal partner, who sold him out at the trial to receive a much lighter sentence. He finds Compeyson, and the two are found fighting by the authorities. Magwitch is exiled to New South Wales, where he works hard and becomes wealthy.
Magwitch never forgets the little boy who helped him and arranges to become Pip's anonymous benefactor. Pip is certain the eccentric Miss Havisham is his benefactor and intends a marriage between him and her beautiful adopted daughter, Estella. Pip doesn't know that Estella is actually the daughter Magwitch fathered and believes to be dead.
Magwitch illegally returns to England to reveal himself to Pip, who is extremely upset to find that the source of his good fortune all these years has been the convict. He eventually warms to Magwitch and tries to help him escape England without being caught. Compeyson once again turns Magwitch in to the authorities. The two fight, and Compeyson is killed.
Magwitch is sentenced to death, but his injuries are so severe he dies in prison. Pip feels compassion for this big-hearted man who has done so much for him and visits him often in the jail. Before Magwitch dies, Pip learns of Estella's true identity and tells his benefactor that his daughter is still living and that he loves her.