Doubleganger Dexter

Dexter & Watchmen's Rorschach are very similar, as he is a serial killer who kills serial killers

Could Dexter be modeled after Rorschach, the watchmen original comic book was written in 1986

Rorschach was created by Watchmen writer Alan Moore with artist Dave Gibbons

Rorschach has no "super powers". He merely has his will and technical abilities. Rorschach uses any and all weapons that are available at the time, such as pepper to blind a police officer and the use of hairspray in combination with a match to set fire to another police officer, as well as Moloch's house. He owns a gas-powered grappling gun, which he uses to climb buildings, as seen in Chapter 1, which was designed and built by Nite Owl II.

Rorschach is well versed in street combat and boxing. In the course of the limited series he demonstrated the ability to best multiple armed assailants with little difficulty. Rorschach demonstrated that he was relatively indifferent to physical pain and discomfort. Due to his time in juvenile detention facilities and group homes as a child he is as street savvy as any criminal. Rorschach also demonstrated the ability to break into a variety of locked buildings and homes, suggesting the expertise of a master thief. http://en.wikipedia.org/wiki/Rorschach_(comics)

Both have connections with Molech - Molech chases Dexters demon, where Rorschach's life as a "masked adventurer" involved fighting gang warfare and masked villains such as Moloch the Mystic. Dexter is too an dark adventurer.