The story of Lord Death Man is a retelling of an earlier story in the American Batman comics. In it, Death-Man appears as a man in a skeleton costume wearing a baggy skull mask over his face. His most notable power is the apparent ability to come back from the dead.
He first appears robbing a gem dealer that Bruce Wayne and Dick Grayson are attending with a gang of armed hoods dressed similarly. Batman and Robin are able to apprehend him following the robbery.
Later, at his sentencing, he is sentenced to death only to apparently suffer a fatal heart attack whilst mocking the judge for believing he can sentence Death-Man to death. Batman and Robin attend his funeral. In fact, they are the only people attending aside from the grave digger. That night, Bruce has a nightmare of Death-Man mocking him for trying to prosecute a dead man. Thinking a change of scenery is needed, Bruce and Dick vacation in Jamaica. While they are vacatation, the hear news that Death-Man has killed again, despite being dead.
The Dynamic Duo hunt down Death-Man in the Batcopter and chase him to a junkyard. While Robin takes down Death-Man's gang, Batman confronts Death-Man again, only for him to fall dead once more, still grinning "like a vulture that had the last laugh". Once again, Death-Man is buried.
While attending a side show of a magician being buried alive, Batman realizes that Death-Man has been faking his deaths using yoga. Batman digs up his coffin only to find a note mocking him. Death-Man confronts Batman once more in the graveyard while a lightning storm is going on. During his battle with Batman, he is able to successfully shoot Batman in the arm before being struck dead by lightning attracted by the gun.
The Death Man Batman and Robin fought years ago has traveled to Japan as "Lord Death Man" to kill all of the Japanese super heros and take the country for his own. One of his earliest targets is the original Mr. Unknown who he murders by breaking pouring acid all over him. When Mr. Unknown's body double Jiro Osamu sees the crime, Lord Death Man sends his henchmen after him, but Jiro gets away.
Lord Death Man then captures Jiro's girlfriend, which leads Jiro to shoot him multiple times, causing Lord Death Man to plumet out a three story window. When Batman and Catwoman come to break up the fight, Batman concludes Lord Death Man has received some "upgrades." Those upgrades include being able to come back from the dead, as he wakes up mid autopsy, and murders many civilians in a hospital.
Lord Death Man races towards his next target, Aquazon of the Super Young Team, but is eventually defeated for good by Batman, Catwoman and Jiro (dressed as Mr. Unknown.) Knowing that Lord Death Man will never be able to die, thus will do anything he can to escape capture, Batman decides to give him a fate "worse than death" and launches Lord Death Man into deep space, never to be seen again.
However, during the Outsiders infiltration of Leviathan Orbital HQ, they come across Lord Death Man (who has seemed to off escaped Batman's deep-space
containment capsule). He laughs and exclaims, "Welcome to the Dead Heroes Club!" (referencing Grant Morrison's earlier Club of Heroes story in Batman: The Black Glove) as the entire space station is blown up from the inside.
It is presumed that both Lord Death Man and the Outsiders are killed (however with Lord Death Man's talent for escaping death, this may not be the case!)
Batman: Brave and the Bold
In the episode "Bat-Mite Presents Batman's Strangest Cases!", Lord Death Man appears in an adaptation of the manga story. The story is mostly faithful to the origanal, save for the implication that he parachuted to safety following a collision with power lines. Bat-Mite implicates this was a change in "the American dub", lampshading the segment being done in the style of early anime.