Originally Cain was merely a host character of the anthology House of Mystery and there he appeared alongside many other characters that Neil Gaiman would eventually take and mold into much more fantastic creations which he did in The Sandman.
Cain first appeared in The House of Mystery #175 created by Bob Haney, Jack Sparling and Joe Orlando.
Cain was originally the host of The House of Mystery in the 1970's, along side his brother Cain who hosted the House of Secrets. He was typical of horror anthologies of the time, which had a host character to introduce the various disconnected stories featured within.
Like many DC horror characters, he was revived in Alan Moore's Saga of the Swamp Thing and eventually in Neil Gaiman's The Sandman where he became a recurring character. He was also a recurring character in the spin-off titles The Dreaming and The House of Mystery.
Cain is the brother of Abel, and the son of Eve, though apart from that he is loosely based on the character in the book of Genesis, well that and the fact that he's constantly murdering his brother Abel. He is the keeper of mysteries, and lived next to his brother Abel (the keeper of secrets) in the Dreaming. Cain can not be killed (at least not easily or without cost) because of the mark on his forehead that God cursed him with after Cain committed the very first murder by killing his brother, Able. During the destruction of the Dreaming, caused by Lyta Hall, Abel is slain by the Furies. Cain rescues Abel's baby gargoyle, Goldie, and takes it to Dream's palace where he meets the Corinthian, Lucien, and Daniel. After all is said and done and Daniel becomes the new Dream of the Endless; after this transformation Cain confronts Dream (Daniel) about his brother's death. As he says he is part of a double act, and he demands that Dream restore Abel. After telling Cain that he is Dream of the Endless and that he will not be ordered about, or threatened by Cain, the new Dream revives Abel.
Major Story Arcs
House of Mystery (Vertigo)
Cain has recently come out of retirement in the comic book world after his shining performance in The Sandman with the new House of Mystery volume in which his House of Mystery went missing and he began a quest to gain it back by working with the Conception, who have a completely different agenda that happens to work alongside his goals. Eventually he and Administrator Ceorel came upon the House in the Space Between but they were trapped there and it was only thanks to Fig making a deal with the Conception that they could leave, however where they ended up with the House was the goblin market which Fig could not leave and Cain refused to, therefore they are currently fighting for control over the House of Mystery which has become something of a tavern where stories are told by the customers that do not have money to pay for there drinks.
The customers tell there stories to keep the time flowing by quickly. Cain goes a bit crazy sometimes or a bit overboard when he tells bad stories. Cain and his House OF Mystery with Fig are traveling in the sky back in Fig past. Cain told her that if there is no way back I am going by myself. Cain and Fig over the door and the House OF Mystery landed back at a goblin town. The towns people look at Cain and Fig they where happy to see them also there bar and house back. Cain and Fig ran when the ghosts killed the goblins they ran and split there own ways. Cain will be seeing again but sadly he will not have his house back Fig's Grandfather put a bomb ball there and it blew up the House of Mystery there will be a new House of Mystery with new guest's at the house. Cain will be very upset. Cain was hiding in the cemetery to be with his thoughts and plans about his House of Mystery and a stranger came by and told him that his house was gone and there is a new House of Mystery.
Cain was upset to her his house was gone and he got up and told the stranger lets go and find out what happened to the House of Mystery. Cain is teamed up with a old 1930's gangster and two ladies to defeat the new manager magic powers and try to regain ownership of the New House of Mystery that is his. Cain and his new team are planing how to get the House of Mystery back to him thew way it was and Mack's grandfather came and told Cain that his granddaughter is having a affair with some one and that he was trapped in the glass bottle and he escape and he wanted to be on the new team with Cain. Cain accepted and welcome him to the new team. After the events in the Vertigo comics they ended the House of Mystery at issue #42.