Hitman

And here you go, not a superhero as such, but a minor character in the DC universe, Hitman, a nice Garth Ennis series about the professional hitman, Tommy Monaghan, a small time guy in Gotham, with minor powers like x-ray vision and telepathy.
The series don't take itself too seriousy, with stuff like zombie dolphins, and my favorite, Tommy puking all over Batman :)


Hitman chronicles the exploits of Tommy Monaghan, an ex-Marine Gulf War veteran turned contract killer from the Cauldron, a lower-class Irish district of Gotham City. He first appears in The Demon Annual #2 (part of the "Bloodlines" crossover in the summer of 1993), when he is attacked and bitten by a Bloodlines parasite called Glonth. Instead of dying, the bite unexpectedly triggers his metagene and grants him x-ray vision and moderate telepathy. A side effect is that his corneas and irises are solid black, indistinguishable from his pupils; the sight managed to unnerve Batman when he first saw them. The inherited powers later come with limits, however, and Monaghan uses them selectively, both because of the difficulty of concentrating during an explosive firefight and the side effects of their extended use (which includes anything between a headache and a minor illness).

After gaining these powers, Monaghan decides to specialize in killing metahumans and supernatural threats, targets typically shunned by conventional contract killers as too dangerous or too expensive. Despite his powers, Monaghan relies most on his creativity, improvisational abilities, and impressive gunfighting skills to take down a majority of his targets. This specialty line of work gives him an edge over his competition, but also leads him to encountering a number of eclectic characters including demons, zombies, dinosaurs, gods, superheroes and supervillains, as well as more conventional, realistic characters such as CIA agents, the SAS and the Mafia.

The series is firmly entrenched in the DC Universe. Batman, The Joker, Green Lantern, Catwoman, Etrigan the Demon, and Superman all guest star at various points, and joking references are frequently made to then-current DC happenings (such as the long-haired Superman). The series also crossed over with many DC events, including Final Night, One Million, and No Man's Land. There was even a one-shot pairing Monaghan with Lobo, and Monaghan has made a few appearances outside of the series (see below).

Although the character adopts the moniker "Hitman" in his first appearance, he only refers to himself by that name once in his own series, in the very first issue; the rest of the time, he is referred to by his given name (although he was sometimes called "Hitman" in guest appearances).