One night, when the Ghostmaker had nothing to do (as he often did because it didn't take long to make ghosts) he was looking through the newspaper as usual to find a good story for which he could make a ghost to haunt the world forever. The Ghostmaker had now been alive for many centuries because Ghostmakers don't die of old age and truly no one yet knows whether they could die at all. As you can imagine, the Ghostmaker was not about to try and find out.
Anyway, as he was looking through the paper (particularly looking for car accident stories because there had been a full moon the night before and everyone knows people drive worse on full moon nights) he found a good story about one drunk driver killing someone else in a car accident. The Ghostmaker thought it would be a good moral lesson to haunt that person with the ghost of the dead driver and began immediately to create the ghost of that person.
Since it's incredibly easy to make the ghost of a person, the Ghostmaker liked to add challenge to it by improving on the intelligence of the ghost or improving the detail of the ghost's appearance. As a result of doing this, he made it impossible to catch his ghosts so it would be bad if he made a mistake. Of course, this story needs a conflict so the very next day he realized that he had made a very bad mistake.
The newspaper he subscribed to wasn't a particularly good one. He got it because it was cheap (Ghostmakers don't make much money). This newspaper had a very bad reporter who got the story wrong. The man hadn't died in the accident. The Ghostmaker made a ghost for a living person! That's quite unheard of, and considering the difficulty in catching his ghost he figured it would be faster, easier, and less risky if he just went after the not-quite-dead driver instead.
The Ghostmaker, having been alive for centuries, knew human tendencies pretty well and found it quite easy to fly under the radar and captured the man with ease. They arrived at the Ghostmaker's home and the Ghostmaker gave the man a choice. Since it was technically the Ghostmaker's fault to begin with, the man could either work with the Ghostmaker in making ghosts or else the Ghostmaker would have to kill him. Naturally, the man chose to live and the Ghostmaker untied him.
The man, however, was quite unhappy with the Ghostmaker because the man had been happy with his life and the Ghostmaker took that away from him. Therefore, when the Ghostmaker finished untying the man, the man tripped him and started using all the karate he learned (this man had taken karate as a hobby for years) to make sure the Ghostmaker couldn't fight back.
Now in all of the centuries the Ghostmaker lived, one of the few things he hadn't learned was how to fight and he, therefore, couldn't do anything to stop this man from beating the crap out of him. Once the man was thoroughly convinced that the Ghostmaker wouldn't be able to move, he hit the self-destruct mechanism for the facility and very quickly left.
No one actually saw the Ghostmaker die, but you can sometimes see his ghost appearing at the ruins of his ghostmaking facility.