History in the comics
Kaine was a clone of Peter Parker that was created by Miles Warren. However, since Miles Warren was still perfecting his cloning technique, Kaine soon developed a condition called clone degeneration, the symptoms of which have left him horribly scared.
After seeing the life that Mary Jane and Peter Parker had carved for themselves, Kaine fell into a deep depression. He eventually became filled with guilt and self-pitty, and tried to goad Ben Reilly into ending his suffering by by killing him. When that failed, Kaine turned himself over to the authorities. He intended to to pay for his crimes and spend the rest of his life in jail. However, when word reached him that one of Spider-Man's greatest enemies (Norman Osborn / Green Goblin) had seeminhly returned from the grave, and having learned the fate of Peter and Mary Jane's baby (their child died at birth), Kaine broke out of prison.
Kaine posses the strength, speed and agility of Spider-Man himself, as well as the ability to burn the "Mark of Kaine" onto the skin of his victims. Kaine also recieves prophetic visions of the future from his imperfect spider-sense.
- Kaine was released as a part of the Spider-Man: The Animated Series toy line but did not appear in the series.