Louis DuBois was a post-Civil War plantation owner from New Orleans. DuBois was a cruel master and certain night, he was lured into a trap by their vengeful ex-slaves, who subjected him to a voodoo ritual which transformed him into an undead being. His sister, Dala, who was suspected to be his lover, followed DuBois to the nearby swamp, where he was already transformed into a vampire being and she succumbed to his powers, which transformed her as well. DuBois became known as "The Monk" and for decades, the two of them preyed upon the innocent until they eventually set their focus in Gotham City.
As part of their plan, Dala attended to Gotham University to find a suitable prey and she came across Dick Grayson, eventually luring him to their retreat, where the Monk knocked him unconscious. The Monk and Dala then used Robin to lure Batman to their lair and The Monk bit Batman, transforming him into an undead.
The Monk was finally confronted and defeated by Batman in his vampiric form, after which the Monk's blood was used to create a cure for Batman and Robin. When they returned to normal, the Monk and Dala were taken by Father Green to the church of St. Jude, where they'd be helped with their eternal curse.
- Vampirism: In addition to the various mental and physical benefits that vampires are heir to, they also possess the ability to turn others into vampires as well. Each new vampire is traditionally subservient to the one who "turned" them, but some strong-willed vampires have been known to rebel against their masters.
- Enhanced Senses: A vampire's senses are enhanced far beyond those of a normal human being.
- Immortality: So long as vampires continue to consume blood, they will not age beyond the physical state they were in when they first became a vampire.
- Invulnerability: Vampires are invulnerable to most forms of injury (certain exceptions apply). Bullets, blades and blunt objects do little to no damage to a vampire's body.
- Regeneration: In addition to being virtually indestructible, whatever damage a vampire does in fact suffer can be healed through the consumption of human blood.
- Superhuman Strength: A vampire's strength level is several times that of a normal human being and they are considered superhuman.
- Superhuman Stamina: So long as they continue to consume human blood, a vampire can function tirelessly without rest or relaxation. However, a vampire's stamina wanes the closer it is to sunrise.
- Psychokinesis: Most vampires possess some form of psychokinesis. Some are clairvoyant, others can communicate telepathically, some possess mind control. Particularly powerful vampires can control the minds of several people at once.
- Transformation: Vampires often possess the ability to transform into a variety of creatures or effects such as bats, wolves, rats or even mist. While their physical attributes may fluctuate during such states, a vampire's mental acuity is the same as that when they are in their human shape. A vampire who transforms into an animal may also benefit from that particular animal's attributes including razor-sharp claws, fangs or the ability to fly.
- Metamorphosis: Vampires often demonstrate the ability to alter their appearance at will.
- This version of The Monk, including all history and corresponding appearances, was erased from existence following the collapse of the original Multiverse in the 1985–86 Crisis on Infinite Earths limited series. Even though versions of the character may have since appeared, this information does not apply to those versions.
- 7 Appearances of Louis DuBois (Earth-One)
- 4 Images featuring Louis DuBois (Earth-One)
- 1 Quotations by or about Louis DuBois (Earth-One)
- Character Gallery: Louis DuBois (Earth-One)