Leatherface

First appearance: The Texas Chainsaw Massacre (1974)

A group of annoying kids run afoul of a Texas family with a strange BBQ recipe. Screaming ensues. There's really not much more to the plot than that.

Some folk consider it a classic of the genre, sadly I'm not one of those people. I prefer the later entries in the series. Although I don't think you are supposed to Enjoy Texas Chainsaw Massacre so in that case it might be the most effective of the Chainsaw flicks.
The franchise has become one of the most convoluted of the Classic Slasher Franchises (Halloween, Friday the 13th, Nightmare on Elm Street, Child's Play) with numerous restarts prequels and remakes. This is how the franchise looks as of August 22, 2014:

• The Texas Chainsaw Massacre (1974)
• The Texas Chainsaw Massacre 2 (1986)
• Leatherface: The Texas Chainsaw Massacre III (1990), considering the end of Chainsaw 2 this could be a reboot although it does have a 3 in the title...
• The Texas Chainsaw Massacre: The Next Generation (1994) Probably a reboot, the only character from the first one in this is Leatherface although he behaves a little differently than in the previous movies and there doesn't seem to be any cannibalism.  It stars Matthew McConaughey and Renée Zellweger. It's got a weird Illuminati storyline explaining that maybe the Sawyers are controlled by some kind of shadowy organization. I like to pretend that McConaughey's character in True Detective is the same guy he plays in this movie only here he's in deep cover and that's why Rust Cole so conspiracy minded in TD. But I digress...
• The Texas Chainsaw Massacre (2003) The first "for sure" remake. They change the name of the family for some reason.
• The Texas Chainsaw Massacre: The Beginning (2006) The Prequel to the remake
• Texas Chainsaw 3-D (2013) Claims to be a direct sequel to the original 1974 The Texas Chainsaw Massacre which I guess ignores the original Texas Chainsaw Massacre 2?
• Leatherface: The Texas Chainsaw Massacre Prequel (201X) just announced prequel to the 1974 The Texas Chainsaw Massacre, not to be confused with Letherface: The Texas Chainsaw Massacre III or The Texas Chainsaw Massacre: The Beginning or The Texas Chainsaw Massacre: The Next Generation.

They've recently released a cleaned up version of the film in theatres. I've seen it and although I'm not a fan of the film, it is the best looking and sounding the movie has ever been.

F. W. Colqhoun

First Appearance: Ravenous (1999)

After a mission goes terribly wrong during the Mexican-American war, Second Lieutenant Boyd's courage fails him and he plays dead as the rest of his unit is massacred around him. The bodies of his fellow soldiers are transported back to the Mexican headquarters. While buried under a pile of his fellow soldiers he is suddenly struck with a sense of bravery and he captures the Mexican command.
As reward for this he is promoted. Unfortunately for (now Captain) Boyd his commanding officer learns of the cowardice that lead to the victory and sends him to Fort Spencer in the Sierra Nevada Mountain range.
While at the fort a stranger named Colqhoun shows up. He claims he was part of a wagon train that became lost and was reduced to cannibalism to survive. The people at the fort mount a rescue attempt, but is this Colqhoun all he appears to be?

This is definitely one of my favourite movies about cannibalism. I really enjoyed the use of native myths used to describe what was happening to some of the characters. It's also got a really interesting score, not something you hear all the time. The gore seems strangely understated and yet not for the week of stomach. I think because the director was a vegetarian the scenes of people enjoying steaks and big Old West meaty meals are handled in a way that really makes the food unappetizing, just to keep you in Boyd's headspace for much of the story. You may not want to eat stew after watching this movie.

Daddy

First appearance: The People Under the Stairs (1991)

I don't know why but I've always enjoyed this weird movie about incestuous cannibals kidnapping people to pretend to be their kids and feeding on the poor. Weirdly hilarious. Apparently its a metaphor for "Reaganomics."The cannibal angle makes him a slasher in my books, even though he used a shotgun for most of his killing.