In DC Comics lore, the Dollmaker is one of Batman's many villains. His real name is Barton Mathis, and after a traumatic childhood of abuse at the hands of his father (who was also a serial killer — and a cannibal), he becomes a serial killer in his own right. His modus operandi is to take the body parts and skin of his victims and fashion them into "dolls."
In its March 2 episode, Fox's Gotham is introducing a character named "Dr. Francis Dulmacher," played by actor Colm Feore. The character is described in press materials as a "mad European scientist." Unless "Dulmacher" is an alias, it sounds like Gotham is reinterpreting the Dollmaker's story, much like the show did with "Ivy Pepper," aka Poison Ivy.
In the comics, Dollmaker has two claims to fame that could prove particularly relevant to Gotham. First, there's more than one character in the DC universe that's used the name Dollmaker. The most famous is a man named Barton Mathis, and he also has the distinction of being a "new" villain to Batman's mythology, having debuted after the "New 52" reboot in 2011. Arrow used the Barton Mathis Dollmaker in a couple of Season 2 episodes, so that's likely related to Gotham renaming its Dollmaker.
One other interesting fact about the Dollmaker: in DC Comics, he cuts off the Joker's face, at Joker's own behest. And yes, it's just as twisted and disgusting as it sounds.
On Gotham, the debut of the Dollmaker has been building for a while. He was first mentioned as working behind the scenes on a child trafficking ring, which he used to harvest body parts for "experiments." He was heard from again more recently, as being responsible for the kidnapping of crime lord Fish Mooney.
Dollmaker's first true episode is called "Everyone Has a Cobblepot." Here's Fox's description of the episode:
While Gordon seeks information about the recent controversy with Commissioner Loeb, Fish's allegiance with the prisoners is questioned when she appears to join forces with Dr. Dulmacher. Meanwhile, after an attack close to home, Bruce deals with the aftermath.
Could it be a coincidence that Dollmaker is premiering in the episode right after the one that (might have) introduced Joker? Hmm.